diff --git a/src/main/java/au/com/royalpay/payment/manage/system/core/beans/TradeSecureFile.java b/src/main/java/au/com/royalpay/payment/manage/system/core/beans/TradeSecureFile.java
index 5b7e8c9e0..76b558dc8 100644
--- a/src/main/java/au/com/royalpay/payment/manage/system/core/beans/TradeSecureFile.java
+++ b/src/main/java/au/com/royalpay/payment/manage/system/core/beans/TradeSecureFile.java
@@ -65,7 +65,7 @@ public class TradeSecureFile {
     }
 
     public String filename() {
-        return String.join("_", transDate.toString("yyMMdd"), pid, createTime.toString("yyMMddHHmmss"));
+        return String.join("_", transDate.toString("yyMMdd"), pid, createTime.toString("yyMMddHHmmss")) + ".txt";
     }
 
     public byte[] content() {