diff --git a/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs b/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs
index 469ece6..05a8f3c 100644
--- a/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs
+++ b/YD_AllHeartRates.Api/Services/Impl/HeartRateReportHelper.cs
@@ -14,39 +14,38 @@ namespace YD_AllHeartRates.Api.Services.Impl
 
         public static ChartDataDto BuildHeartRateTrend(List<HeartRateData> data)
         {
+            // 固定时间段：8点到16点
+            var fixedHours = Enumerable.Range(8, 9).ToList(); // 8~16 共9小时
+            var axisX = fixedHours.Select(h => $"{h}:00").ToList();
+
+            var axisY = new List<int>();
+
             if (data == null || data.Count == 0)
-                return new ChartDataDto()
+            {
+                // 无数据时返回默认0值
+                axisY = Enumerable.Repeat(0, fixedHours.Count).ToList();
+            }
+            else
+            {
+                // 按小时分组计算平均值（四舍五入）
+                var hourlyAvg = data
+                    .GroupBy(x => x.ScoreTime.Hour)
+                    .ToDictionary(g => g.Key, g => (int)Math.Round(g.Average(x => x.Value)));
+
+                foreach (var hour in fixedHours)
                 {
-                    AxisX = new List<string>() { "8:00", "9:00", "10:00", "11:00", "12:00", "13:00", "14:00", "15:00", "16:00" },
-                    AxisY = new List<int>() { 0, 0, 0, 0, 0, 0, 0, 0, 0 }
-                };
-
-            // 按小时分组计算平均值（四舍五入）
-            var hourlyAvg = data
-                .GroupBy(x => x.ScoreTime.Hour)
-                .ToDictionary(g => g.Key, g => (int)Math.Round(g.Average(x => x.Value)));
-
-            // 获取最小和最大小时
-            int minHour = data.Min(x => x.ScoreTime.Hour);
-            int maxHour = data.Max(x => x.ScoreTime.Hour);
-
-            var chart = new ChartDataDto
-            {
-                AxisX = new List<string>(),
-                AxisY = new List<int>()
-            };
-
-            for (int hour = minHour; hour <= maxHour; hour++)
-            {
-                chart.AxisX.Add($"{hour}:00");  // 去掉前导0
-                chart.AxisY.Add(hourlyAvg.TryGetValue(hour, out int val) ? val : 80);
+                    axisY.Add(hourlyAvg.TryGetValue(hour, out int val) ? val : 80); // 缺省用80填充
+                }
             }
 
-            return chart;
+            return new ChartDataDto
+            {
+                AxisX = axisX,
+                AxisY = axisY
+            };
         }
 
 
-
         public static int CalculateReachRate(int reachCount, int total)
             => total == 0 ? 0 : (int)((double)reachCount / total * 100);