Abstract: In this paper, the optimal planning of electric - gas multi energy system is studied to improve the efficiency of comprehensive energy utilization. Considering the demand of multiple energy sources in the integrated energy system, an optimization model of the electric-gas system is established. The model considers the economic and safety reliability optimization objectives, considers the system constraints in the form of different energy requirements, and the weighted Voronoi diagram algorithm is used to solve the problem. Finally, a specific example is given, and the results show that the model and algorithm presented in this paper can provide an integrated energy system optimization program.