diff --git a/apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/PropertiesUtilTest.java b/apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/PropertiesUtilTest.java
index 396042cb612..ad54fd3589d 100644
--- a/apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/PropertiesUtilTest.java
+++ b/apollo-core/src/test/java/com/ctrip/framework/apollo/core/utils/PropertiesUtilTest.java
@@ -56,5 +56,9 @@ public void testFilterPropertiesComment() {
     PropertiesUtil.filterPropertiesComment(sb3);
     assertEquals("bbb", sb3.toString());
     assertNotEquals("#aaaaa" + System.lineSeparator() + "bbb", sb3.toString());
+    
+    StringBuffer sb4 = new StringBuffer("#aaaa");
+    PropertiesUtil.filterPropertiesComment(sb4);
+    assertEquals("#aaaa", sb4.toString());
   }
 }