diff --git a/backend/plugins/domain/user/handlers.go b/backend/plugins/domain/user/handlers.go
index 08c88c7a..08287794 100644
--- a/backend/plugins/domain/user/handlers.go
+++ b/backend/plugins/domain/user/handlers.go
@@ -12,8 +12,6 @@ import (
 	"strconv"
 	"time"
 
-	database "Wavelet/plugins/infra/database"
-
 	"Wavelet/core/contracts"
 	"Wavelet/pkg/response"
 	"github.com/gin-contrib/sessions"
@@ -136,7 +134,7 @@ func Register(c *gin.Context) {
 		return
 	}
 
-	gormDB := database.DB(c.Request.Context())
+	gormDB := getDB(c.Request.Context())
 	if err := gormDB.Create(newUser).Error; err != nil {
 		response.AbortBadRequest(c, "创建用户失败: "+err.Error())
 		return
@@ -183,7 +181,7 @@ func ChangePassword(c *gin.Context) {
 		return
 	}
 
-	gormDB := database.DB(c.Request.Context())
+	gormDB := getDB(c.Request.Context())
 	_ = gormDB.Save(&user)
 	invalidateUserCache(c.Request.Context(), user.ID)
 
@@ -213,7 +211,7 @@ func UpdateProfile(c *gin.Context) {
 	user.Website = req.Website
 	user.Location = req.Location
 
-	gormDB := database.DB(c.Request.Context())
+	gormDB := getDB(c.Request.Context())
 	_ = gormDB.Save(&user)
 	invalidateUserCache(c.Request.Context(), user.ID)
 
@@ -224,7 +222,7 @@ func UpdateProfile(c *gin.Context) {
 func ListAccessTokens(c *gin.Context) {
 	userID := getUserIDFromSession(c)
 	var tokens []AccessToken
-	gormDB := database.DB(c.Request.Context())
+	gormDB := getDB(c.Request.Context())
 	_ = gormDB.Where("user_id = ?", userID).Find(&tokens).Error
 	c.JSON(http.StatusOK, response.OK(tokens))
 }
@@ -262,7 +260,7 @@ func CreateAccessToken(c *gin.Context) {
 		IsAdmin:     req.IsAdmin,
 	}
 
-	gormDB := database.DB(c.Request.Context())
+	gormDB := getDB(c.Request.Context())
 	if err := gormDB.Create(&token).Error; err != nil {
 		response.AbortInternal(c, "创建令牌失败")
 		return
@@ -285,7 +283,7 @@ func DeleteAccessToken(c *gin.Context) {
 
 	userID := getUserIDFromSession(c)
 	var token AccessToken
-	gormDB := database.DB(c.Request.Context())
+	gormDB := getDB(c.Request.Context())
 	if err := gormDB.Where("id = ? AND user_id = ?", id, userID).First(&token).Error; err != nil {
 		response.AbortNotFound(c, errTokenNotFound)
 		return
@@ -307,7 +305,7 @@ func RotateAccessToken(c *gin.Context) {
 
 	userID := getUserIDFromSession(c)
 	var token AccessToken
-	gormDB := database.DB(c.Request.Context())
+	gormDB := getDB(c.Request.Context())
 	if err := gormDB.Where("id = ? AND user_id = ?", id, userID).First(&token).Error; err != nil {
 		response.AbortNotFound(c, errTokenNotFound)
 		return
diff --git a/backend/plugins/domain/user/plugin.go b/backend/plugins/domain/user/plugin.go
index 11a49a10..d091e61f 100644
--- a/backend/plugins/domain/user/plugin.go
+++ b/backend/plugins/domain/user/plugin.go
@@ -7,6 +7,7 @@ package user
 import (
 	"context"
 	"embed"
+	"reflect"
 
 	"Wavelet/core"
 	"Wavelet/core/contracts"
@@ -52,6 +53,13 @@ func (p *Plugin) Name() string {
 	return PluginName
 }
 
+// Inject declares required dependencies for the user domain plugin.
+func (p *Plugin) Inject() []reflect.Type {
+	return []reflect.Type{
+		reflect.TypeFor[contracts.DBService](),
+	}
+}
+
 // Manifest returns the plugin metadata.
 func (p *Plugin) Manifest() core.Manifest {
 	return core.Manifest{
@@ -64,7 +72,12 @@ func (p *Plugin) Manifest() core.Manifest {
 
 // Apply registers user migrations, services, routes, tasks, schedules, and settings into the Context.
 func (p *Plugin) Apply(ctx *core.Context) error {
-	// 0. Resolve auth service for middleware (via IoC, not direct import)
+	// 0. Bind DBService from Context
+	if db, err := core.Inject[contracts.DBService](ctx); err == nil && db != nil {
+		setDBService(db)
+	}
+
+	// 0.1 Resolve auth service for middleware (via IoC, not direct import)
 	var loginMW gin.HandlerFunc = func(c *gin.Context) { c.Next() }
 	var noTokenMW gin.HandlerFunc = func(c *gin.Context) { c.Next() }
 	if authSvc, err := core.Inject[contracts.AuthService](ctx); err == nil && authSvc != nil {
diff --git a/backend/plugins/domain/user/plugin_test.go b/backend/plugins/domain/user/plugin_test.go
index 95365e37..fc30d164 100644
--- a/backend/plugins/domain/user/plugin_test.go
+++ b/backend/plugins/domain/user/plugin_test.go
@@ -36,7 +36,10 @@ func setupTestDB(t *testing.T) *gorm.DB {
 
 func TestUserPluginUnit(t *testing.T) {
 	ctx := core.NewContext(context.Background())
-	_ = setupTestDB(t)
+	testDB := setupTestDB(t)
+
+	dbPlugin := database.New(database.WithDB(testDB))
+	require.NoError(t, dbPlugin.Apply(ctx))
 
 	p := user.New()
 	assert.Equal(t, "user", p.Name())
diff --git a/backend/plugins/domain/user/repository.go b/backend/plugins/domain/user/repository.go
index 804b1bf7..04ae495c 100644
--- a/backend/plugins/domain/user/repository.go
+++ b/backend/plugins/domain/user/repository.go
@@ -5,18 +5,47 @@ package user
 
 import (
 	"context"
-
 	"strings"
+	"sync"
 
+	"Wavelet/core"
+	"Wavelet/core/contracts"
 	"Wavelet/pkg/util"
-	database "Wavelet/plugins/infra/database"
 	"gorm.io/gorm"
 )
 
+var (
+	dbMu  sync.RWMutex
+	dbSvc contracts.DBService
+)
+
+func setDBService(s contracts.DBService) {
+	dbMu.Lock()
+	defer dbMu.Unlock()
+	dbSvc = s
+}
+
+func getDB(ctx context.Context) *gorm.DB {
+	if c, ok := ctx.(*core.Context); ok && c != nil {
+		if s := c.DB(); s != nil {
+			return s.DB(ctx)
+		}
+	}
+
+	dbMu.RLock()
+	s := dbSvc
+	dbMu.RUnlock()
+	if s != nil {
+		return s.DB(ctx)
+	}
+
+	return nil
+}
+
 // GetUserByID 通过 ID 获取用户
 func GetUserByID(ctx context.Context, id uint64) (*User, error) {
 	var u User
-	if err := database.DB(ctx).First(&u, id).Error; err != nil {
+	if err := getDB(ctx).First(&u, id).Error; err != nil {
 		return nil, err
 	}
 	return &u, nil
@@ -25,7 +54,7 @@ func GetUserByID(ctx context.Context, id uint64) (*User, error) {
 // GetUserByUsername 通过用户名获取用户
 func GetUserByUsername(ctx context.Context, username string) (*User, error) {
 	var u User
-	if err := database.DB(ctx).Where("username = ?", username).First(&u).Error; err != nil {
+	if err := getDB(ctx).Where("username = ?", username).First(&u).Error; err != nil {
 		return nil, err
 	}
 	return &u, nil
@@ -34,7 +63,7 @@ func GetUserByUsername(ctx context.Context, username string) (*User, error) {
 // GetUserByEmail 通过邮箱获取用户
 func GetUserByEmail(ctx context.Context, email string) (*User, error) {
 	var u User
-	if err := database.DB(ctx).Where("email = ?", email).First(&u).Error; err != nil {
+	if err := getDB(ctx).Where("email = ?", email).First(&u).Error; err != nil {
 		return nil, err
 	}
 	return &u, nil
@@ -42,17 +71,17 @@ func GetUserByEmail(ctx context.Context, email string) (*User, error) {
 
 // CreateUser 创建用户
 func CreateUser(ctx context.Context, u *User) error {
-	return database.DB(ctx).Create(u).Error
+	return getDB(ctx).Create(u).Error
 }
 
 // UpdateUser 更新用户
 func UpdateUser(ctx context.Context, u *User) error {
-	return database.DB(ctx).Save(u).Error
+	return getDB(ctx).Save(u).Error
 }
 
 // ListUsers 分页查询用户
 func ListUsers(ctx context.Context, page, pageSize int, keyword string) ([]*User, int64, error) {
-	db := database.DB(ctx).Model(&User{})
+	db := getDB(ctx).Model(&User{})
 	if keyword != "" {
 		escaped := util.EscapeLike(keyword)
 		db = db.Where("username LIKE ? ESCAPE '\\' OR nickname LIKE ? ESCAPE '\\' OR email LIKE ? ESCAPE '\\'", "%"+escaped+"%", "%"+escaped+"%", "%"+escaped+"%")
@@ -74,7 +103,7 @@ func ListUsers(ctx context.Context, page, pageSize int, keyword string) ([]*User
 // GetAccessTokenByHash 通过 Hash 查询访问令牌
 func GetAccessTokenByHash(ctx context.Context, tokenHash string) (*AccessToken, error) {
 	var token AccessToken
-	if err := database.DB(ctx).Where("token_hash = ?", tokenHash).First(&token).Error; err != nil {
+	if err := getDB(ctx).Where("token_hash = ?", tokenHash).First(&token).Error; err != nil {
 		return nil, err
 	}
 	return &token, nil
@@ -90,7 +119,7 @@ type AdminUserListFilter struct {
 
 // ListAdminUsers 获取后台管理用户列表
 func ListAdminUsers(ctx context.Context, filter AdminUserListFilter) (int64, []User, error) {
-	query := database.DB(ctx).Model(&User{})
+	query := getDB(ctx).Model(&User{})
 	if filter.Username != "" {
 		escaped := util.EscapeLike(strings.ToLower(filter.Username))
 		query = query.Where("LOWER(username) LIKE ? ESCAPE '\\'", "%"+escaped+"%")
@@ -116,13 +145,13 @@ func ListAdminUsers(ctx context.Context, filter AdminUserListFilter) (int64, []U
 
 // UpdateUserActive 更新用户激活状态
 func UpdateUserActive(ctx context.Context, id uint64, active bool) error {
-	return database.DB(ctx).Model(&User{}).Where("id = ?", id).Update("is_active", active).Error
+	return getDB(ctx).Model(&User{}).Where("id = ?", id).Update("is_active", active).Error
 }
 
 // GetActiveUserByID 获取处于激活状态的用户
 func GetActiveUserByID(ctx context.Context, id uint64) (*User, error) {
 	var u User
-	if err := database.DB(ctx).Where("id = ? AND is_active = ?", id, true).First(&u).Error; err != nil {
+	if err := getDB(ctx).Where("id = ? AND is_active = ?", id, true).First(&u).Error; err != nil {
 		return nil, err
 	}
 	return &u, nil
@@ -130,7 +159,7 @@ func GetActiveUserByID(ctx context.Context, id uint64) (*User, error) {
 
 // DeleteUserWithRelations 删除用户及其级联关系
 func DeleteUserWithRelations(ctx context.Context, id uint64) error {
-	return database.DB(ctx).Transaction(func(tx *gorm.DB) error {
+	return getDB(ctx).Transaction(func(tx *gorm.DB) error {
 		if err := tx.Where("user_id = ?", id).Delete(&AccessToken{}).Error; err != nil {
 			return err
 		}
@@ -141,7 +170,7 @@ func DeleteUserWithRelations(ctx context.Context, id uint64) error {
 // GetFirstAdminUser 获取第一个管理员用户
 func GetFirstAdminUser(ctx context.Context) (*User, error) {
 	var u User
-	if err := database.DB(ctx).Where("is_admin = ?", true).Order("id ASC").First(&u).Error; err != nil {
+	if err := getDB(ctx).Where("is_admin = ?", true).Order("id ASC").First(&u).Error; err != nil {
 		return nil, err
 	}
 	return &u, nil
@@ -151,7 +180,7 @@ func GetFirstAdminUser(ctx context.Context) (*User, error) {
 func ListUsernamesMatchingBase(ctx context.Context, base string) ([]string, error) {
 	var usernames []string
 	escaped := util.EscapeLike(strings.ToLower(base))
-	if err := database.DB(ctx).Model(&User{}).
+	if err := getDB(ctx).Model(&User{}).
 		Where("LOWER(username) LIKE ? ESCAPE '\\'", escaped+"%").
 		Pluck("username", &usernames).Error; err != nil {
 		return nil, err
diff --git a/backend/plugins/domain/user/service.go b/backend/plugins/domain/user/service.go
index d37ea440..b764570f 100644
--- a/backend/plugins/domain/user/service.go
+++ b/backend/plugins/domain/user/service.go
@@ -14,7 +14,6 @@ import (
 	"Wavelet/core"
 	"Wavelet/core/contracts"
 	"Wavelet/pkg/idgen"
-	database "Wavelet/plugins/infra/database"
 	"gorm.io/gorm"
 
 	pkgu "Wavelet/pkg/util"
@@ -75,7 +74,7 @@ func (s *userServiceImpl) GetUserByUsername(ctx context.Context, username string
 
 func (s *userServiceImpl) GetUserByEmail(ctx context.Context, email string) (*contracts.UserDTO, error) {
 	var u User
-	if err := database.DB(ctx).Where("email = ?", email).First(&u).Error; err != nil {
+	if err := getDB(ctx).Where("email = ?", email).First(&u).Error; err != nil {
 		return nil, err
 	}
 	return toUserDTO(&u), nil
@@ -143,7 +142,7 @@ func (s *userServiceImpl) UpdateProfile(ctx context.Context, id uint64, req cont
 	}
 	updates[columnUpdatedAt] = time.Now()
 
-	if err := database.DB(ctx).Model(&User{}).Where("id = ?", id).Updates(updates).Error; err != nil {
+	if err := getDB(ctx).Model(&User{}).Where("id = ?", id).Updates(updates).Error; err != nil {
 		return nil, err
 	}
 
@@ -152,7 +151,7 @@ func (s *userServiceImpl) UpdateProfile(ctx context.Context, id uint64, req cont
 
 func (s *userServiceImpl) UpdatePassword(ctx context.Context, id uint64, oldPassword, newPassword string) error {
 	var user User
-	if err := database.DB(ctx).Where("id = ?", id).First(&user).Error; err != nil {
+	if err := getDB(ctx).Where("id = ?", id).First(&user).Error; err != nil {
 		return err
 	}
 
@@ -164,7 +163,7 @@ func (s *userServiceImpl) UpdatePassword(ctx context.Context, id uint64, oldPass
 		return err
 	}
 
-	return database.DB(ctx).Model(&User{}).Where("id = ?", id).
+	return getDB(ctx).Model(&User{}).Where("id = ?", id).
 		Updates(map[string]any{
 			"password":      user.Password,
 			columnUpdatedAt: time.Now(),
@@ -173,7 +172,7 @@ func (s *userServiceImpl) UpdatePassword(ctx context.Context, id uint64, oldPass
 
 func (s *userServiceImpl) VerifyPassword(ctx context.Context, id uint64, password string) bool {
 	var user User
-	if err := database.DB(ctx).Where("id = ?", id).First(&user).Error; err != nil {
+	if err := getDB(ctx).Where("id = ?", id).First(&user).Error; err != nil {
 		pkgu.DummyCheckPassword(password)
 		return false
 	}
@@ -181,7 +180,7 @@ func (s *userServiceImpl) VerifyPassword(ctx context.Context, id uint64, passwor
 }
 
 func (s *userServiceImpl) UpdateLastLogin(ctx context.Context, id uint64, _ string) error {
-	return database.DB(ctx).Model(&User{}).Where("id = ?", id).
+	return getDB(ctx).Model(&User{}).Where("id = ?", id).
 		Updates(map[string]any{
 			"last_login_at": time.Now(),
 			columnUpdatedAt: time.Now(),
@@ -220,7 +219,7 @@ func (s *userServiceImpl) SetUserActive(ctx context.Context, id uint64, active b
 }
 
 func (s *userServiceImpl) SetUserAdmin(ctx context.Context, id uint64, admin bool) error {
-	return database.DB(ctx).Model(&User{}).Where("id = ?", id).Update("is_admin", admin).Error
+	return getDB(ctx).Model(&User{}).Where("id = ?", id).Update("is_admin", admin).Error
 }
 
 func (s *userServiceImpl) VerifyAccessToken(ctx context.Context, tokenHash string) (*contracts.UserDTO, bool, error) {
@@ -243,13 +242,13 @@ func (s *userServiceImpl) DeleteUser(ctx context.Context, id uint64) error {
 
 func (s *userServiceImpl) CountUsers(ctx context.Context) (int64, error) {
 	var count int64
-	err := database.DB(ctx).Model(&User{}).Count(&count).Error
+	err := getDB(ctx).Model(&User{}).Count(&count).Error
 	return count, err
 }
 
 func (s *userServiceImpl) CountActiveUsers(ctx context.Context) (int64, error) {
 	var count int64
-	err := database.DB(ctx).Model(&User{}).Where("is_active = ?", true).Count(&count).Error
+	err := getDB(ctx).Model(&User{}).Where("is_active = ?", true).Count(&count).Error
 	return count, err
 }
 
@@ -292,7 +291,7 @@ func (s *userServiceImpl) UniqueUsername(ctx context.Context, base string) (stri
 }
 
 func (s *userServiceImpl) AdminListUsers(ctx context.Context, filter contracts.AdminListUsersFilter) (int64, []*contracts.UserDTO, error) {
-	query := database.DB(ctx).Table("w_users")
+	query := getDB(ctx).Table("w_users")
 	if filter.UserID != nil {
 		query = query.Where("id = ?", *filter.UserID)
 	}
@@ -330,7 +329,7 @@ func (s *userServiceImpl) AdminListUsers(ctx context.Context, filter contracts.A
 
 func (s *userServiceImpl) AdminGetUser(ctx context.Context, id uint64) (*contracts.UserDTO, error) {
 	var user contracts.UserDTO
-	if err := database.DB(ctx).Table("w_users").
+	if err := getDB(ctx).Table("w_users").
 		Select("id, username, nickname, email, avatar_url, is_active, is_admin, bio, phone, gender, website, location, last_login_at, created_at, updated_at").
 		Where("id = ?", id).
 		First(&user).Error; err != nil {
@@ -357,7 +356,7 @@ func (s *userServiceImpl) AdminCreateUser(ctx context.Context, req contracts.Adm
 	}
 
 	var count int64
-	if err := database.DB(ctx).Table("w_users").Where("username = ?", req.Username).Count(&count).Error; err != nil {
+	if err := getDB(ctx).Table("w_users").Where("username = ?", req.Username).Count(&count).Error; err != nil {
 		return nil, err
 	}
 	if count > 0 {
@@ -365,7 +364,7 @@ func (s *userServiceImpl) AdminCreateUser(ctx context.Context, req contracts.Adm
 	}
 
 	var emailCount int64
-	if err := database.DB(ctx).Table("w_users").Where("email = ?", req.Email).Count(&emailCount).Error; err != nil {
+	if err := getDB(ctx).Table("w_users").Where("email = ?", req.Email).Count(&emailCount).Error; err != nil {
 		return nil, err
 	}
 	if emailCount > 0 {
@@ -404,7 +403,7 @@ func (s *userServiceImpl) AdminCreateUser(ctx context.Context, req contracts.Adm
 		"created_at":    now,
 		columnUpdatedAt: now,
 	}
-	if err := database.DB(ctx).Table("w_users").Create(row).Error; err != nil {
+	if err := getDB(ctx).Table("w_users").Create(row).Error; err != nil {
 		return nil, err
 	}
 
@@ -428,7 +427,7 @@ func (s *userServiceImpl) AdminUpdateUser(ctx context.Context, currentUserID uin
 	}
 
 	var targetUser contracts.UserDTO
-	if err := database.DB(ctx).Table("w_users").Where("id = ?", req.ID).First(&targetUser).Error; err != nil {
+	if err := getDB(ctx).Table("w_users").Where("id = ?", req.ID).First(&targetUser).Error; err != nil {
 		return err
 	}
 
@@ -438,7 +437,7 @@ func (s *userServiceImpl) AdminUpdateUser(ctx context.Context, currentUserID uin
 
 	if targetUser.Email != req.Email {
 		var count int64
-		if err := database.DB(ctx).Table("w_users").Where("email = ? AND id != ?", req.Email, req.ID).Count(&count).Error; err != nil {
+		if err := getDB(ctx).Table("w_users").Where("email = ? AND id != ?", req.Email, req.ID).Count(&count).Error; err != nil {
 			return err
 		}
 		if count > 0 {
@@ -469,7 +468,7 @@ func (s *userServiceImpl) AdminUpdateUser(ctx context.Context, currentUserID uin
 		updates["password"] = hash
 	}
 
-	err := database.DB(ctx).Table("w_users").Where("id = ?", req.ID).Updates(updates).Error
+	err := getDB(ctx).Table("w_users").Where("id = ?", req.ID).Updates(updates).Error
 	if err == nil && s.events != nil {
 		_ = s.events.Emit(ctx, contracts.EventTopicUserUpdated, &targetUser)
 	}
@@ -481,14 +480,14 @@ func (s *userServiceImpl) AdminUpdateUserStatus(ctx context.Context, id uint64,
 		ID      uint64
 		IsAdmin bool
 	}
-	if err := database.DB(ctx).Table("w_users").Select("id, is_admin").Where("id = ?", id).First(&flags).Error; err != nil {
+	if err := getDB(ctx).Table("w_users").Select("id, is_admin").Where("id = ?", id).First(&flags).Error; err != nil {
 		return err
 	}
 	if !active && flags.IsAdmin {
 		return errors.New("管理员账号无法被禁用")
 	}
 
-	err := database.DB(ctx).Table("w_users").Where("id = ?", id).Update("is_active", active).Error
+	err := getDB(ctx).Table("w_users").Where("id = ?", id).Update("is_active", active).Error
 	if err == nil && s.events != nil {
 		_ = s.events.Emit(ctx, contracts.EventTopicUserStatusChanged, contracts.UserStatusChangedEvent{
 			UserID:   id,
@@ -506,14 +505,14 @@ func (s *userServiceImpl) AdminDeleteUser(ctx context.Context, currentUserID, ta
 		ID      uint64
 		IsAdmin bool
 	}
-	if err := database.DB(ctx).Table("w_users").Select("id, is_admin").Where("id = ?", targetID).First(&flags).Error; err != nil {
+	if err := getDB(ctx).Table("w_users").Select("id, is_admin").Where("id = ?", targetID).First(&flags).Error; err != nil {
 		return err
 	}
 	if flags.IsAdmin {
 		return errors.New("管理员账号无法被删除")
 	}
 
-	err := database.DB(ctx).Transaction(func(tx *gorm.DB) error {
+	err := getDB(ctx).Transaction(func(tx *gorm.DB) error {
 		if err := tx.Table("w_access_tokens").Where("user_id = ?", targetID).Delete(map[string]any{}).Error; err != nil {
 			return err
 		}