diff --git a/eventmesh-runtime/src/test/java/org/apache/eventmesh/runtime/util/IOTinyUtilsTest.java b/eventmesh-runtime/src/test/java/org/apache/eventmesh/runtime/util/IOTinyUtilsTest.java
index 52ce3ec9ca..ff36b29a0c 100644
--- a/eventmesh-runtime/src/test/java/org/apache/eventmesh/runtime/util/IOTinyUtilsTest.java
+++ b/eventmesh-runtime/src/test/java/org/apache/eventmesh/runtime/util/IOTinyUtilsTest.java
@@ -30,8 +30,9 @@
 import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileOutputStream;
-import java.io.FileWriter;
 import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.List;
 
@@ -66,7 +67,7 @@ public void testToString() throws IOException {
         File temp = null;
         try {
             temp = File.createTempFile("temp", ".txt");
-            BufferedWriter bw = new BufferedWriter(new FileWriter(temp));
+            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(temp), StandardCharsets.UTF_8));
             bw.write("test toString");
             bw.close();
             String res = IOTinyUtils.toString(Files.newInputStream(temp.toPath()), EventMeshConstants.DEFAULT_CHARSET);