The invention relates to a graywater contamination collecting system for a vehicle, a control method and a vehicle. The graywater contamination collecting system for the vehicle comprises a graywaterdrainage device, a graywater temporary storage box, a water closet, a water tank, a graywater contamination box, a flushing switch and an electric control unit; the water tank is connected with a water flushing pipe of the water closet through a water supply pipeline; a booster water pump, an energy storage tank and a water flushing electromagnetic valve are connected to the water flushing pipe inseries in sequence, wherein the booster water pump is used for increasing the water flushing pressure; the energy storage tank is used for temporarily storing pressure water; and the water flushing electromagnetic valve is used for controlling the closing and opening of the water flushing pipe; the bottom of the water closet is connected with the graywater contamination box through a blow-off pipe; the graywater drainage device is connected with the graywater temporary storage box through a first water drainage pipe; the graywater temporary storage box is connected with the graywater contamination box through a second water drainage pipe; a first electric gate valve is arranged on the blow-off pipe; a second electric gate valve is connected to the second water drainage pipe in series; anelectric vacuum pump used for keeping a vacuum state of the graywater contamination box is connected to the graywater contamination box; and the flushing switch, the water flushing electromagnetic valve, the first electric gate valve, the second electric gate valve, the booster water pump and the electric vacuum pump are connected with the electric control unit. The graywater contamination collecting system for the vehicle has the characteristics of less system equipment, simple and compact structure, low fault rate, guaranteed water flushing effect and the like.