The invention provides a compressed-air automatic spraying device and system. The automatic spraying device comprises a spray head, an air pipe, a water pipe and a water storage device, wherein, the water storage device is respectively connected with the air pipe, the water pipe and the spray head; the water pipe is equipped with a water valve; the air pipe is equipped with an air pipe spring switch; and the air pipe spring switch is connected to the outer wall of the water storage device through a rope. The compressed-air automatic spraying device and system provided by the invention have the advantages of overcoming the defect of the prior art that gas explosion is easily caused when an electric control automatic spraying device or an acoustic control automatic spraying device is applied to a working environment of a coal mine with higher gas content, and achieving the purpose of regularly and safely performing automatic spray by virtue of compressed air.