Aiming at the protection strategy of trajectory coating for wall-climbing spraying on ship’s outer panel, a design of wall-climbing robot with reciprocating spray gun is proposed. From the system point of view, the overall design of the robot’s dragging wall climbing body system, feeding and paint mist recovery protective cover system, safety protection system and trajectory planning were carried out. The design problems of each part were refined and analyzed separately, and the corresponding countermeasures were put forward. This wall-climbing robot can simulate manual work, and can perform multi-machine linkage wall-attaching operation according to the two-machine operation control process, which provides reference value for the practical application of mechanization in ship intelligent manufacturing production.