diff --git a/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs b/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs
index 8777e94..39cc409 100644
--- a/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs
+++ b/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs
@@ -14,16 +14,23 @@ namespace YD_AllHeartRates.Api.Services.Impl
 
         public static ChartDataDto BuildHeartRateTrend(List<HeartRateData> data)
         {
+            if (data == null || data.Count == 0)
+                return new ChartDataDto();
+
+            // 按小时分组计算平均值（四舍五入）
             var hourlyAvg = data
                 .GroupBy(x => x.ScoreTime.Hour)
-                .OrderBy(g => g.Key)
                 .ToDictionary(g => g.Key, g => (int)Math.Round(g.Average(x => x.Value)));
 
+            // 获取最小和最大小时
+            int minHour = data.Min(x => x.ScoreTime.Hour);
+            int maxHour = data.Max(x => x.ScoreTime.Hour);
+
             var chart = new ChartDataDto();
-            foreach (var hour in hourlyAvg.Keys)
+            for (int hour = minHour; hour <= maxHour; hour++)
             {
                 chart.AxisX.Add($"{hour:00}:00");
-                chart.AxisY.Add(hourlyAvg[hour]);
+                chart.AxisY.Add(hourlyAvg.TryGetValue(hour, out int val) ? val : 0);
             }
 
             return chart;