diff --git a/plugins/stats_dashboard/templates/index.html b/plugins/stats_dashboard/templates/index.html
index aca8966..26142da 100644
--- a/plugins/stats_dashboard/templates/index.html
+++ b/plugins/stats_dashboard/templates/index.html
@@ -140,7 +140,8 @@
                 topUsers: [],
                 topGroups: [],
                 topPlugins: [],
-                pluginStats: []
+                pluginStats: [],
+                charts: {}  // 添加charts对象
             }
         },
         mounted() {
@@ -286,10 +287,15 @@
                 const ctx = document.getElementById('trendChart').getContext('2d');
                 
                 // 销毁旧图表
-                if (this.charts.trendChart) {
+                if (this.charts && this.charts.trendChart) {
                     this.charts.trendChart.destroy();
                 }
                 
+                // 确保charts对象存在
+                if (!this.charts) {
+                    this.charts = {};
+                }
+                
                 // 准备数据
                 const labels = trendData.map(item => item.stat_date);
                 const totalData = trendData.map(item => item.total_calls);
@@ -330,6 +336,7 @@
                     },
                     options: {
                         responsive: true,
+                        maintainAspectRatio: false,
                         scales: {
                             y: {
                                 beginAtZero: true