On condition of unmanned system and secondary integration，the necessity of taking a new look at the substation control layer architecture is discussed，and the control layer architecture is put forward.It is proposed that，with the smart gateway device as the core，the monitor terminal should be used to take the place of the local backstage，the isolated information problem be solved and unified remote transmission of all substation business data ensured.The functional orientation and the relation between smart gateway and monitor terminal are presented.And such key technologies as the graph data model conversion between the substation and master station，substation remote transmission protocol，registration and publication，source maintenance，and realization of advanced applications in the smart gateway are also discussed.