The invention relates to a pressure reducing faucet water separator for a water purifier. The pressure reducing faucet water separator comprises a pressure regulating cavity and a water separation cavity communicating with the pressure regulating cavity. A pressure reducing device is arranged in the pressure regulating cavity. The pressure reducing device comprises a rubber ball capable of moving in the vertical direction and a valve seat body capable of moving in the vertical direction. The rubber ball is suspended under a water inlet of the pressure regulating cavity. The valve seat body is arranged under the rubber ball. The pressure regulating cavity is vertically divided into an air cylinder communicating with external air and a water accumulation cavity communicating the water inlet of the pressure regulating cavity with the water separation cavity. The valve seat body moves vertically according to changes of the water volume in the water accumulation cavity. The valve seat body pushes the rubber ball to vertically move to regulate the circulation amount of water flowing in from the water inlet of the pressure regulating cavity. According to the pressure reducing faucet water separator for the water purifier, a water separator body and the pressure reducing device are combined into the water separator with the pressure reducing effect. The problem of damage to the water purifier due to high water pressure is solved.