diff --git a/fe/fe-common/src/main/java/org/apache/doris/catalog/ScalarType.java b/fe/fe-common/src/main/java/org/apache/doris/catalog/ScalarType.java
index b4a81068b3f270..6f684471e56c6f 100644
--- a/fe/fe-common/src/main/java/org/apache/doris/catalog/ScalarType.java
+++ b/fe/fe-common/src/main/java/org/apache/doris/catalog/ScalarType.java
@@ -578,7 +578,7 @@ public static ScalarType createHllType() {
     public String toString() {
         if (type == PrimitiveType.CHAR) {
             if (isWildcardChar()) {
-                return "CHARACTER";
+                return "CHARACTER(" + MAX_CHAR_LENGTH + ")";
             }
             return "CHAR(" + len + ")";
         } else  if (type == PrimitiveType.DECIMALV2) {
@@ -614,7 +614,7 @@ public String toSql(int depth) {
         switch (type) {
             case CHAR:
                 if (isWildcardChar()) {
-                    stringBuilder.append("CHARACTER");
+                    stringBuilder.append("CHARACTER").append("(").append(MAX_CHAR_LENGTH).append(")");
                 } else if (Strings.isNullOrEmpty(lenStr)) {
                     stringBuilder.append("CHAR").append("(").append(len).append(")");
                 } else {
diff --git a/fe/fe-core/src/test/java/org/apache/doris/catalog/CreateFunctionTest.java b/fe/fe-core/src/test/java/org/apache/doris/catalog/CreateFunctionTest.java
index 7c9a45febaea3f..76f54eea9f63ad 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/catalog/CreateFunctionTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/catalog/CreateFunctionTest.java
@@ -285,7 +285,7 @@ public void testCreateGlobalFunction() throws Exception {
         testFunctionQuery(ctx, queryStr, true);
 
         queryStr = "select to_char(k1, 4) from db2.tbl1;";
-        Assert.assertTrue(dorisAssert.query(queryStr).explainQuery().contains("CAST(`k1` AS CHARACTER)"));
+        Assert.assertTrue(dorisAssert.query(queryStr).explainQuery().contains("CAST(`k1` AS CHARACTER(255))"));
     }
 
     private void testFunctionQuery(ConnectContext ctx, String queryStr, Boolean isStringLiteral) throws Exception {