diff --git a/braintree.md b/braintree.md
index e42e358..22a0e58 100644
--- a/braintree.md
+++ b/braintree.md
@@ -19,7 +19,7 @@
 |reference|M|商户系统交易请求流水号|
 |terminal|M|交易类型|
 |vendor|M|支付/收款方式|
-|verifySign|API请求签名|
+|verifySign|M|API请求签名|
 
 ```json
 {