Substation is the core hub of power system. With the expansion of the scale of the power system and the improvement of its intelligence, the problems of the redundancy of architecture and equipment in the protection and monitoring system of substation can no longer be ignored. This paper proposes an evaluation method for integration in the protection and monitoring system based on G1 method. Firstly, according to the requirements of integration in the protection and monitoring system, the corresponding indicators are proposed to form an index system for evaluating integration. And then, an evaluation method is proposed for integration of the protection and monitoring system, based on G1 method and expert investigation. Finally, the feasibility of the evaluation method is verified by comparing and analyzing the evaluation results of a typical substation and its structural optimization substation.