The purpose of this paper is to provide the reasonable design of operation parameters for the combined heat-supply system by obtaining the optimal allocation proportion based on the groundwater heat pump and boiler plant. Combined with the engineering example, based on the groundwater heat pump and coal-consuming boiler, the optimal distribution proportion of the combined heat-supply system is obtained by energy consumption analysis for heat load duration graph, economic analysis with annual cost method and simulation of the combined system. Combined heating of coal-consuming boiler and groundwater heat pump in the optimal load distribution proportion not only reduces the initial investment of heat source system, but greatly reduces the total energy consumption, prolongs the performance period of the boiler, and improves the utilization efficiency of the boiler as well. Meanwhile, the combined system has the lowest annual cost and the best economy.