The invention discloses a vehicle cleaning system and method for a construction site. The vehicle cleaning system comprises a water storage tank, a controller, a water delivery pump, a water suction pump, a lateral flushing frame, water distribution pipes, a filtering pool, a sedimentation tank and a water filtering pool, wherein the water suction pump is used for connecting the water storage tankand the water filtering pool, the water delivery pump is connected with one ends of the water distribution pipes, the water distribution pipes are arranged on the filtering pool, the lateral flushingframe is arranged between the water distribution pipes, nozzles are uniformly distributed on the lateral flushing frame, a bearing plate and a U-shaped water spraying pipe are correspondingly arranged between the water distribution pipes, and the U-shaped water spraying pipe is movably connected with a bending nozzle. The cleaning method comprises the following steps of (a) parking cleaning, (b)moving cleaning and c) waste water circulating. The cleaning system is novel in structure, wide in flushing range, high in cleaning efficiency, and good, comprehensive and thorough in cleaning effect,water resources are recycled, the cost is reduced, the cleaning method is orderly conducted by steps, the labor is saved, convenience and rapidity are realized, control is easy, and the cleaning effect and the cleaning quality are ensured.