The invention provides a regional integrated energy system energy storage configuration method considering an electric/thermal flexible load, and the method comprises the steps: firstly comprehensively analyzing the composition of the electric load and the thermal transmission characteristics of a heat supply system, and building an electric/thermal flexible load model; then, on the basis of the architecture of the known regional integrated energy system, establishing a model of each energy assembly, meanwhile, setting constraint conditions, including energy balance constraint, energy assembly output constraint, tie line transmission power constraint and energy storage constraint; secondly, considering system energy consumption, investment, operation and maintenance and compensation cost, and establishing an economic single-objective optimization model; and finally, based on the LINGO18.0 software, solving the established energy storage optimal configuration model to obtain the optimal output of each device and the optimal capacities of the storage battery and the heat storage tank. According to the method, the regional comprehensive energy system is subjected to energy storage optimization configuration, and the energy utilization efficiency is improved.