diff --git a/backend/api/internal/seed/mock.go b/backend/api/internal/seed/mock.go
index 3c8fcff..59f27ee 100644
--- a/backend/api/internal/seed/mock.go
+++ b/backend/api/internal/seed/mock.go
@@ -2,6 +2,7 @@
 package seed
 
 import (
+	"errors"
 	"fmt"
 	"reflect"
 	"time"
@@ -437,36 +438,40 @@ func MockData(database *gorm.DB) error {
 			return err
 		}
 
-		role := models.PlatformRole{
-			Entity: entity(45, common.StatusEnable), RoleCode: "mock_operator",
-			Name: "模拟运营人员", LocationScope: "standard", IsSystem: false,
-		}
-		if err := put(tx, &role); err != nil {
-			return err
-		}
-
-		platformAccount := models.PlatformAccount{
-			Entity: entity(46, common.StatusEnable), Username: "mock_operator",
-			DisplayName: "模拟运营人员", PasswordHash: string(passwordHash),
-			PlatformRoleCode: role.RoleCode, Phone: "13600000001",
-		}
-		if err := put(tx, &platformAccount); err != nil {
-			return err
-		}
-
-		roleMenu := models.PlatformRoleMenu{
-			PlatformRoleID: role.ID, MenuIdentity: "dashboard_overview",
-		}
-		if err := tx.Where(
-			"platform_role_id = ? AND menu_identity = ?",
-			role.ID, roleMenu.MenuIdentity,
-		).FirstOrCreate(&roleMenu).Error; err != nil {
-			return fmt.Errorf("seed platform_role_menu: %w", err)
-		}
-		return nil
+		return ensureMockRoot(tx, string(passwordHash))
 	})
 }
 
+// ensureMockRoot 复用已有 root 账号，仅在账号不存在时写入默认 root 用户。
+func ensureMockRoot(database *gorm.DB, passwordHash string) error {
+	role := models.PlatformRole{
+		Entity: entity(45, common.StatusEnable), RoleCode: "root",
+		Name: "系统管理员", LocationScope: "precise", IsSystem: true,
+	}
+	if err := database.Where("role_code = ?", role.RoleCode).FirstOrCreate(&role).Error; err != nil {
+		return fmt.Errorf("seed root platform role: %w", err)
+	}
+
+	var account models.PlatformAccount
+	err := database.Where("username = ?", "root").First(&account).Error
+	if err == nil {
+		return nil
+	}
+	if !errors.Is(err, gorm.ErrRecordNotFound) {
+		return fmt.Errorf("find root platform account: %w", err)
+	}
+
+	account = models.PlatformAccount{
+		Entity: entity(46, common.StatusEnable), Username: "root",
+		DisplayName: "平台根管理员", PasswordHash: passwordHash,
+		PlatformRoleCode: role.RoleCode,
+	}
+	if err := database.Create(&account).Error; err != nil {
+		return fmt.Errorf("seed root platform account: %w", err)
+	}
+	return nil
+}
+
 func entity(sequence int, status int) models.Entity {
 	return models.Entity{
 		Identity: fmt.Sprintf("%s%012d", mockIdentityPrefix, sequence),