At present, ship wall cleaning is important in the marine engineering equipment maintenance industry. Designing permanent magnetic adsorption units is one of the most important ways to implement efficient, environmentally friendly, high-quality ship cleaning work. In this paper, theoretical design tests and technical studies are carried out on the permanent magnetic crawler structure of the ship cleaning and wall climbing robot, and the adsorption method, walking method, magnetic material and permanent magnetic adsorption structure of the ship cleaning and wall climbing robot are comprehensively analyzed and selected. Finally, the design of the permanent magnetic crawler for the ship cleaning and wall climbing robot is proposed.