diff --git a/internal/models/send_stats.go b/internal/models/send_stats.go
index 68b6f11..44ceb88 100644
--- a/internal/models/send_stats.go
+++ b/internal/models/send_stats.go
@@ -1,18 +1,16 @@
 package models
 
 import (
-	"time"
-
 	"baihu/internal/constant"
 )
 
 // SendStats 任务执行统计
 type SendStats struct {
-	ID        uint      `json:"id" gorm:"primaryKey"`
-	TaskID    uint      `json:"task_id" gorm:"index"`
-	Status    string    `json:"status" gorm:"size:20;not null"` // success, failed
-	Num       int       `json:"num" gorm:"default:0"`
-	CreatedAt time.Time `json:"created_at"`
+	ID     uint   `json:"id" gorm:"primaryKey"`
+	TaskID uint   `json:"task_id" gorm:"uniqueIndex:idx_task_day_status"`
+	Day    string `json:"day" gorm:"size:10;uniqueIndex:idx_task_day_status"` // 格式: 2006-01-02
+	Status string `json:"status" gorm:"size:20;uniqueIndex:idx_task_day_status"`
+	Num    int    `json:"num" gorm:"default:0"`
 }
 
 func (SendStats) TableName() string {
diff --git a/internal/services/send_stats_service.go b/internal/services/send_stats_service.go
index 6e7e2f0..facc89a 100644
--- a/internal/services/send_stats_service.go
+++ b/internal/services/send_stats_service.go
@@ -15,19 +15,18 @@ func NewSendStatsService() *SendStatsService {
 
 // IncrementStats 增加任务执行统计
 func (s *SendStatsService) IncrementStats(taskID uint, status string) error {
-	today := time.Now().Format("2006-01-02")
-	startOfDay, _ := time.ParseInLocation("2006-01-02", today, time.Local)
+	day := time.Now().Format("2006-01-02")
 
 	var stats models.SendStats
-	result := database.DB.Where("task_id = ? AND status = ? AND created_at >= ?", taskID, status, startOfDay).First(&stats)
+	result := database.DB.Where("task_id = ? AND day = ? AND status = ?", taskID, day, status).First(&stats)
 
 	if result.Error != nil {
 		// 不存在则创建
 		stats = models.SendStats{
-			TaskID:    taskID,
-			Status:    status,
-			Num:       1,
-			CreatedAt: time.Now(),
+			TaskID: taskID,
+			Day:    day,
+			Status: status,
+			Num:    1,
 		}
 		return database.DB.Create(&stats).Error
 	}
@@ -39,25 +38,22 @@ func (s *SendStatsService) IncrementStats(taskID uint, status string) error {
 // GetStatsByTaskID 获取任务的统计数据
 func (s *SendStatsService) GetStatsByTaskID(taskID uint) []models.SendStats {
 	var stats []models.SendStats
-	database.DB.Where("task_id = ?", taskID).Order("created_at DESC").Find(&stats)
+	database.DB.Where("task_id = ?", taskID).Order("day DESC").Find(&stats)
 	return stats
 }
 
 // GetTodayStats 获取今日统计
 func (s *SendStatsService) GetTodayStats() []models.SendStats {
-	today := time.Now().Format("2006-01-02")
-	startOfDay, _ := time.ParseInLocation("2006-01-02", today, time.Local)
-
+	day := time.Now().Format("2006-01-02")
 	var stats []models.SendStats
-	database.DB.Where("created_at >= ?", startOfDay).Find(&stats)
+	database.DB.Where("day = ?", day).Find(&stats)
 	return stats
 }
 
 // GetRecentStats 获取最近N天的统计
 func (s *SendStatsService) GetRecentStats(days int) []models.SendStats {
-	startDate := time.Now().AddDate(0, 0, -days)
-
+	startDay := time.Now().AddDate(0, 0, -days).Format("2006-01-02")
 	var stats []models.SendStats
-	database.DB.Where("created_at >= ?", startDate).Order("created_at DESC").Find(&stats)
+	database.DB.Where("day >= ?", startDay).Order("day DESC").Find(&stats)
 	return stats
 }