Abstract:The auxiliary power in power plant plays a crucial role in normal operation of power plant,which ensures the operation of main equipment ( boiler,steam turbine or hydro turbine,generator,control of nuclear reactor core) and other auxiliary equipment.If the auxiliary power has lost the power,the power plant will come to an island operation and the security of main and auxiliary equipment will be severely affected,even resulting in a serious consequence. The actual situation of power plant,the kinds of potential accidents,even the influence of disasters on the island operation of power plant are discussed,and the remarkable matters and resolution methods are proposed so as to enhance the security and reliability of auxiliary power,which will reduce the effects and hazards on the staff and equipment.