The utility model discloses a combined construction site vehicle washing facility. The combined construction site vehicle washing facility is characterized by comprising a vehicle washing tank, a wading pool and an automatic spray-washing device, wherein the wading pool is connected with the vehicle washing tank, water spraying pipelines of the automatic spray-washing device are arranged at the two sides of the vehicle washing tank, and water baffles are arranged on the vehicle washing tank; the vehicle washing tank is connected with a water converging ditch, and the water converging ditch is connected with a precipitation tank; the wading pool is connected with the water converging ditch through a drainage ditch. The combined construction site vehicle washing facility can be applicable to a construction site with large vehicle washing capacity and high washing requirements; the combined construction site vehicle washing facility is reasonable in structural design, strong in universality and simple in construction process and can be flexibly constructed on site, so that compared with the prior art, the combined construction site vehicle washing facility has the advantages that the pollution to the site and roads resulting from that washing water is splashed outside the vehicle washing tank and dirty water is brought out by vehicle wheels can be effectively avoided, the vehicle wheels are washed more comprehensively and thoroughly, the washing effect is cleaner and more reliable, only one-time investment is required as circulating water is adopted to wash, and thus, the single-time washing cost can be greatly reduced.