diff --git a/src/main/sdk/org/bdware/client/ContractRequest.java b/src/main/sdk/org/bdware/client/ContractRequest.java
index 1d6ec37..4161341 100644
--- a/src/main/sdk/org/bdware/client/ContractRequest.java
+++ b/src/main/sdk/org/bdware/client/ContractRequest.java
@@ -138,11 +138,19 @@ public class ContractRequest extends SM2Verifiable
                 "%s|%s|%s%s|%s",
                 (contractDOI != null && contractDOI.length() > 0) ? contractDOI : contractID,
                 action,
-                arg,
+                parseArg(),
                 gasLimit > 0 ? "|" + gasLimit : "",
                 requester);
     }
 
+    private String parseArg() {
+        try {
+            return arg.getAsString();
+        } catch (Exception e) {
+            return arg.toString();
+        }
+    }
+
     public byte[] toByte() {
         try {
             ByteArrayOutputStream out = new ByteArrayOutputStream();