diff --git a/.gitignore b/.gitignore
index 9edb5d9a..76d9669a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -612,3 +612,4 @@ $RECYCLE.BIN/
 !/dev-support/bin
 /.ionide
 /output
+*.tmp
diff --git a/GeothermalResearchInstitute/GeothermalResearchInstitute.Wpf/ViewModels/DeviceMetricHistoryExportViewModel.cs b/GeothermalResearchInstitute/GeothermalResearchInstitute.Wpf/ViewModels/DeviceMetricHistoryExportViewModel.cs
index 4f5a775c..5a1f9443 100644
--- a/GeothermalResearchInstitute/GeothermalResearchInstitute.Wpf/ViewModels/DeviceMetricHistoryExportViewModel.cs
+++ b/GeothermalResearchInstitute/GeothermalResearchInstitute.Wpf/ViewModels/DeviceMetricHistoryExportViewModel.cs
@@ -170,16 +170,30 @@ await sw
                         + "环境温度（摄氏度）,出水压力（米）,回水压力（米）,"
                         + "加热器功率（千瓦）,水泵流量（立方米/小时）")
                     .ConfigureAwait(true);
+
+                var metricInterval = TimeSpan.FromMinutes(this.IntervalMinutes);
+                DateTimeOffset lastKnownMetricCreateTime = DateTimeOffset.MinValue;
                 foreach (Metric m in metrics)
                 {
+                    DateTimeOffset createTimeThreshold = lastKnownMetricCreateTime
+                        .AddSeconds(metricInterval.TotalSeconds * 0.9);
+
+                    var createTime = m.CreateTime.ToDateTimeOffset();
+                    if (createTime < createTimeThreshold)
+                    {
+                        continue;
+                    }
+
                     await sw
                         .WriteLineAsync(
-                            $"{m.CreateTime.ToDateTimeOffset().ToLocalTime().ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)},"
+                            $"{createTime.ToLocalTime().ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)},"
                             + $"{m.OutputWaterCelsiusDegree:F2},{m.InputWaterCelsiusDegree:F2},"
                             + $"{m.HeaterOutputWaterCelsiusDegree:F2},{m.EnvironmentCelsiusDegree:F2},"
                             + $"{m.OutputWaterPressureMeter:F2},{m.InputWaterPressureMeter:F2},"
                             + $"{m.HeaterPowerKilowatt:F2},{m.WaterPumpFlowRateCubicMeterPerHour:F2}")
                         .ConfigureAwait(true);
+
+                    lastKnownMetricCreateTime = createTime;
                 }
             }
         }