The present invention discloses a power-on/off drive circuit and a method for controlling the power-on/off drive circuit, and belongs to the field of electronic technologies. The power-on/off drive circuit includes a load, a switch circuit, a relay, and a single-source drive circuit; one end of a coil in the relay and a first input end of the single-source drive circuit are separately connected to a positive electrode of a second external power supply, and the other end of the coil in the relay is connected to a second input end of the single-source drive circuit; and a first output end of the single-source drive circuit is connected to a second input end of the switch circuit, a second output end of the single-source drive circuit is connected to the output end of the switch circuit, and a third output end of the single-source drive circuit is connected to a negative electrode of the second external power supply. In the present invention, a volume of a power-on/off drive circuit is reduced.