diff --git a/designer-chart/src/main/java/com/fr/van/chart/map/designer/type/VanChartMapSourceChoosePane.java b/designer-chart/src/main/java/com/fr/van/chart/map/designer/type/VanChartMapSourceChoosePane.java
index dab21dd62..10664b340 100644
--- a/designer-chart/src/main/java/com/fr/van/chart/map/designer/type/VanChartMapSourceChoosePane.java
+++ b/designer-chart/src/main/java/com/fr/van/chart/map/designer/type/VanChartMapSourceChoosePane.java
@@ -381,7 +381,7 @@ public class VanChartMapSourceChoosePane extends JPanel implements UIObserver {
         public void actionPerformed(ActionEvent e) {
 
             new SwingWorker<Void, Double>() {
-                private java.util.List<WMSLayer> list;
+                private java.util.List<WMSLayer> list = new ArrayList<>();
 
                 @Override
                 protected Void doInBackground() throws Exception {