Abstract: A simplified analysis method was proposed for the demand of emergency feedwater by nuclear power plant using steam-driven injector. According to the parameters of AP1000 nulcear power plant, the cooling water demand in primary loop was analyzed during shutdown period, so as to obtain the requirement on performance of the steam-driven injector in the process of hot and cold standby. Results indicate that, the steam-driven injector is required to operate at various cases during shutdown period, so different configurations can be adopted in the design of steam-driven injectors, thus meeting the performance requirement of steam-driven injector through adjustment on relevant steam and water parameters.