diff --git a/reading-platform-frontend/src/views/school/DashboardView.vue b/reading-platform-frontend/src/views/school/DashboardView.vue
index 34b6c26..efd9f31 100644
--- a/reading-platform-frontend/src/views/school/DashboardView.vue
+++ b/reading-platform-frontend/src/views/school/DashboardView.vue
@@ -653,11 +653,13 @@ const loadCourseStats = async () => {
   }
 };
 
-// 加载授课趋势数据
+// 加载授课趋势数据（默认最近 7 天）
 const loadTrendData = async () => {
   trendLoading.value = true;
   try {
-    const data = await getLessonTrend(7);
+    const endDate = new Date().toISOString().split('T')[0];
+    const startDate = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000).toISOString().split('T')[0];
+    const data = await getLessonTrend(startDate, endDate);
     lessonTrendData.value = data;
   } catch (error) {
     console.error('Failed to load trend data:', error);