The invention belongs to the technical field of painting equipment, and particularly discloses an automatic paint spraying device. The automatic paint spraying device comprises a spray gun, a controlunit and a movement unit; the control unit comprises a first button, a second button, a gear rack and a first gear; the movement unit comprises a piston cylinder, a fixing cylinder, a transmission cylinder and a motor; a piston is glidingly connected in the piston cylinder; a pushing column is fixed on the piston; a mounting table is fixed on the pushing column; an outer gear ring is arranged on the outer wall of the mounting table; a cavity is formed in the mounting table; two pressing blocks are glidingly connected inside the cavity; a nut is in threaded connection with the outer wall of thepiston cylinder; the pushing column is fixed on the nut; a pushing plate is glidingly connected in the fixing cylinder; a pressing rod is fixed on the pushing plate; a vent pipe is connected betweenthe fixing cylinder and the piston cylinder; the transmission cylinder is loaded with a transmission medium, and a rotating shaft is rotationally connected inside the transmission cylinder; a pressingplate is in threaded connection with the rotating shaft; and a connecting pipe is connected between the transmission cylinder and the mounting table. By adopting the automatic paint spraying device,the problems that the artificial paint spraying is uneven and an additional drying process needs to be performed after the paint spraying are solved.