diff --git a/src/main/java/run/halo/s3os/UrlUtils.java b/src/main/java/run/halo/s3os/UrlUtils.java
index a1c502c..8b17f87 100644
--- a/src/main/java/run/halo/s3os/UrlUtils.java
+++ b/src/main/java/run/halo/s3os/UrlUtils.java
@@ -21,7 +21,7 @@ public static String removeHttpPrefix(String url) {
 
     public static String findUrlSuffix(List<S3OsProperties.urlSuffixItem> urlSuffixList,
                                        String fileName) {
-        if (StringUtils.isBlank(fileName)) {
+        if (StringUtils.isBlank(fileName) || urlSuffixList == null) {
             return null;
         }
         fileName = fileName.toLowerCase();
diff --git a/src/test/java/run/halo/s3os/UrlUtilsTest.java b/src/test/java/run/halo/s3os/UrlUtilsTest.java
index aecb5a0..02b707b 100644
--- a/src/test/java/run/halo/s3os/UrlUtilsTest.java
+++ b/src/test/java/run/halo/s3os/UrlUtilsTest.java
@@ -46,5 +46,10 @@ public void testFindUrlSuffix() {
         String fileName5 = "";
         String result5 = UrlUtils.findUrlSuffix(urlSuffixList, fileName5);
         assertNull(result5);
+
+        // 测试urlSuffixList为null，期望返回null
+        String fileName6 = "example";
+        String result6 = UrlUtils.findUrlSuffix(null, fileName6);
+        assertNull(result6);
     }
 }
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