The invention relates to an automobile stopper painting device. The automobile stopper painting device comprises a machine box; a feeding opening is processed and formed at the top of the machine box;the feeding opening is in threaded connection with a plug; a paint box is fixed at the top position of the internal part of the machine box through a screw; a transverse sliding rail is fixedly belowthe paint box through a screw; a mounting base is clamped and embedded at the lower end of the transverse sliding rail; a mounting rod is fixed at the lower end of the mounting base through a screw;the lower end of the mounting rod is connected with a painting roller through a rotating shaft; a waste box is embedded at the bottom of the machine box; a telescopic arm is fixed at the front end position of the bottom of the machine box through a screw; a longitudinal sliding rail is fixed at the top of the telescopic arm through a screw; the automobile stopper painting device can perform positioning after an automobile stopper is clamped, is convenient to position and paint, reduces painting blind areas and painting repetition, can move the automobile stopper to the brushing position of thecolor through sliding, can perform coordinated painting work, can increase the painting speed, can bear the overflowing waste paint generated in painting and is convenient to clean.