The invention relates to the technical field of intelligent power grids, in particular to a control method and a system for a substation access control system. The access control system comprises a video environment monitoring platform, a remote processing unit and one or more access controllers; the control method comprises the following steps that the remote processing unit transmits a remote processing unit registration request to the video environment monitoring platform; the video environment monitoring platform returns remote processing unit registration pass information; the access controller transmits an access controller registration request to the remote processing unit; the remote processing unit returns access control unit registration pass information; and the remote processing unit transmits access resource information to the video environment monitoring platform. According to the control method and the system for the substation access control system, the access controllers are integrated to the video environment monitoring platform of the substation through a remote processing unit (RPU), the resource configuration information is in an active push mode, the system configuration and maintenance operation is greatly reduced, and the equipment resource configuration information is synchronized.