A coating device comprises a base, a mounting bracket mounted to the base by a driving mechanism, a coating unit which comprises a supporting rack mounted to the mounting bracket and a nozzle mounted to the supporting rack, and the coating device further comprises a detecting device mounted to the supporting rack, which detects information about a distance between the nozzle and a surface of the substrate to be coated and information about an obstacle on a substrate in an advancing direction of the nozzle; a control unit, which controls to keep the distance to be a preset distance based on the detected distance information, and which controls to stop operation of the nozzle where an obstacle is detected on a region on the surface of the substrate between the detecting device and the nozzle.