There are provided an apparatus and a method for controlling power of a vehicle. The apparatus for controlling power of a vehicle includes: a first load and a second load; a first power supply supplying power to at least one of the first load and the second load from a main battery; a second power supply supplying power to at least one of the first load and the second load from an auxiliary battery supplied with and charged by the power from the main battery; a switch set including a plurality of switches intermitting lines between the first load, the second load, the first power supply, and the second power supply; and a power controller checking a state of the vehicle and controlling a turn-on or off for the plurality of switches in response to the checked state of the vehicle.