For the poor operation reliability and low econom.ic benefit of large.scale wind.solar.storage generation system, thispaper adopts multi.objective gravitational search algorithm(GSA) to optimize capacity allocation of wind.solar.storage generation unit.Power output models of generation unit are established, includingwind turbine model, photovoltaic generator model and storage bat.tery model.Wind speed, irradiation and temperature data of an areafrom January to December in 2015 are used to calculate power out.put of wind turbine and photovoltaic cell.The optimal wind.solar.storage system configuration is obtained with capacity of wind tur.bine, photovoltaic cell and battery as decision variables and mini.mum of cost, loss of power supply probability and energy wastagerate as optimal objective.