Flow of water curtain paint room curtain-like water to collect and take away paint spray, curtain-like layer sets in front of paint mist air flow. Horizontal air spray paint indoors, curtain down like a curtain on the wall right in front of the operator. Under the large upper air exhaust coating spray booth/indoor waterfall is arranged in Chamber floor, ramp placed air punch when it comes to water, paint particle droplet is attached to leaves, water maintained by a special-purpose circulation pump, adjust water control valve, to control curtain shape ' complete.