diff --git a/src/main/java/com/peanut/modules/common/controller/ClassExamController.java b/src/main/java/com/peanut/modules/common/controller/ClassExamController.java
index b2e03539..08bb0e3b 100644
--- a/src/main/java/com/peanut/modules/common/controller/ClassExamController.java
+++ b/src/main/java/com/peanut/modules/common/controller/ClassExamController.java
@@ -50,7 +50,7 @@ public class ClassExamController {
             while (it.hasNext()) {
                 Map.Entry<String, String> entry = it.next();
                 String pos = entry.getKey();
-                String rowNo = pos.substring(1);
+                String rowNo = pos.replaceAll("[a-zA-Z]", "");
                 count = Integer.parseInt(rowNo);
 //                System.out.println(pos + ";" + entry.getValue());
             }