diff --git a/internal/dao/sensor.go b/internal/dao/sensor.go
index 77a299f..c22ba59 100644
--- a/internal/dao/sensor.go
+++ b/internal/dao/sensor.go
@@ -64,7 +64,7 @@ func (dao *SensorDAO) GetAggregatedData(start, end time.Time, interval string) (
 	// 构建通用查询
 	query := `
 		SELECT 
-			MIN(timestamp) as ts,
+			DATE_FORMAT(MIN(timestamp), '%Y-%m-%dT%H:%i:%S') as ts,
 			ROUND(AVG(temperature)/10, 1) as avg_temp,
 			MAX(rainfall) - MIN(rainfall) as rainfall,
 			ROUND(AVG(humidity)/10, 1) as avg_humidity,