The invention discloses an automatic coating structure for brake pads, which includes a conveyor belt transmission mechanism, a conveyor belt tension mechanism, and a constant speed reciprocating coating mechanism. The conveyor belt transmission mechanism includes a frame, a conveyor driven sprocket, a conveyor belt drive Sprocket, gear motor, the gear motor is set on the frame, the gear motor is connected with the driving sprocket of the conveyor belt; the conveying driven sprocket is connected with the sliding bearing seat; It is connected by a conveying chain; the conveyor belt tensioning mechanism includes a lower seat, a sliding bearing seat, an upper sliding seat, and a short-range cylinder tightening rod, and the sliding bearing seat is set on the lower seat and the upper sliding seat; the short-range air cylinder is set on the frame; The ejector rod of the short-range cylinder is connected with a top rod; the constant speed reciprocating coating mechanism includes a nozzle bracket, a rodless cylinder, and a nozzle, and the rodless cylinder is set on the frame; the nozzle bracket is connected to the rodless cylinder; on the stand. The invention has the advantages of simple structure, convenient operation and high production efficiency.