The invention provides a standby power apparatus for a wind power generation unit. The standby power apparatus comprises a standby battery controller and at least two supercapacitor groups; the standby battery controller is connected with a variable pitch system controller of the wind power generation unit and is used for controlling the at least two supercapacitor groups to be connected in parallel or in series according to the working state of the variable pitch system obtained from the variable pitch system controller; and the controller is connected with a direct current bus between a direct current charging power supply and the pitch system through the at least two supercapacitor groups. By adoption of the embodiment of the standby power apparatus for the wind power generation unit, the series-parallel connection of multiple supercapacitor groups can be controlled for providing reliable power supply for the variable pitch system of the wind power generation unit; and the normal operation of the wind power generation unit is further ensured.