diff --git a/src/main/java/mjkf/xinke/main/controller/MaterialController.java b/src/main/java/mjkf/xinke/main/controller/MaterialController.java
index 491c237..63ab4e3 100644
--- a/src/main/java/mjkf/xinke/main/controller/MaterialController.java
+++ b/src/main/java/mjkf/xinke/main/controller/MaterialController.java
@@ -144,7 +144,7 @@ public class MaterialController {
         query.orderByDesc(Material::getId);
         var data = materialService.list(query);
         String maxBrotherId;
-        if (data == null) {
+        if (data == null || data.size() == 0) {
             maxBrotherId = null;
         } else {
             maxBrotherId = data.get(0).getId();
diff --git a/src/main/java/mjkf/xinke/main/service/MaterialService.java b/src/main/java/mjkf/xinke/main/service/MaterialService.java
index 6c7c583..9d3aec8 100644
--- a/src/main/java/mjkf/xinke/main/service/MaterialService.java
+++ b/src/main/java/mjkf/xinke/main/service/MaterialService.java
@@ -11,6 +11,9 @@ public class MaterialService extends ServiceImpl<BaseMapper<Material>, Material>
         String prefix;
         String suffix;
         String previous;
+        if (maxBrotherId == null) {
+            maxBrotherId = "60.60.60.60";
+        }
         if (parentId.contains("00.00.00.00")) {
             prefix = "";
             suffix = ".00.00.00";