An active rectifier for a wireless power transfer system includes: a first rectifying circuit; a second rectifying circuit; a first switching circuit and a second switching circuit. The first rectifying circuit, the second rectifying circuit, the first switching circuit, and the second switching circuit are arranged in a form of a bridge circuit between a secondary coil of a vehicle and a battery of the vehicle, and the active rectifier controls the first and second switching circuits according to a charging status of the battery or an output status of the wireless power transfer system in order to change or maintain a charging power to the battery.