diff --git a/core/Contract.proto b/core/Contract.proto
index 9d0870973c6..b334f7709b0 100644
--- a/core/Contract.proto
+++ b/core/Contract.proto
@@ -29,7 +29,7 @@ message AccountCreateContract {
 }
 
 // update account name if the account has no name.
-message AccountUpdateContract{
+message AccountUpdateContract {
   bytes account_name = 1;
   bytes owner_address = 2;
 }
@@ -92,8 +92,8 @@ message AssetIssueContract {
 message ParticipateAssetIssueContract {
   bytes owner_address = 1;
   bytes to_address = 2;
-  bytes asset_name = 3;
-  int64 amount = 4;
+  bytes asset_name = 3; // the name of target asset
+  int64 amount = 4; // the amount of drops
 }
 
 message DeployContract {