From your screenshot it doesn’t look like it’s granted? 

Thanks for your reply.

It has been granted in other permission sets.

I haven’t granted it after creating the new method,  then it has been granted.

I want to know why it is automaticly granted.

Database object grants are stored in two tables:

• One table stores grants for whole packages.
• One table stores revocations for package methods (procedures and functions).

To access a package method, the permission set must be granted permission on the package itself, and there must not exist a revocation for that permission set against that particular method. By default, this opens up the whole package until the methods are then individually revoked.

Since no record will exist for a new method before it’s added to a package, it will be automatically granted to any permission sets that access to the package itself.

Thank you! It helps me a lot!