The invention discloses an environment-friendly building pipe paint spraying device. The environment-friendly building pipe paint spraying device comprises a rack, a conveying motor is arranged on oneside of the rack, a toothed bar is arranged on one side of the inner wall of the rack, a conveying roller is arranged in the rack, the conveying roller is fixedly connected with the conveying motor,a conveying belt is arranged on the outer side of the conveying roller, a clamping mechanism is arranged on the surface of the conveying belt, a box body is arranged at the upper end of the rack, an air suction pump is arranged at the upper end of the box body, the air suction pump communicates with the box body, the exhaust end of the air suction pump is provided with an exhaust pipe connected with a water box, a bearing plate is arranged in the box body, and a nozzle is arranged at the bottom of the bearing plate. The device has the beneficial effects that automatic conveying and automatic paint spraying of pipes can be achieved, the paint spraying effect is good, the efficiency is high, in the paint spraying process, paint mist generated by paint spraying can be absorbed, and the phenomenon that due to paint mist drifting, the health of an operator is affected is avoided.