In order to solve the inconvenience of manual rust removal on the hull surface, a crawler type water jet wall climbing rust removal robot was designed, and a permanent magnet adsorption design was carried out. Firstly, according to the overall structure and design index of the robot, the adsorption force of a single magnet to ensure the static stability of the robot should reach 800 N. Maxwell was used to optimize the parameters of the magnet model. The maximum adsorption force of five 15 mm thick N-S positive and negative magnetic circuit magnets was determined to be 3 163.8 N, and the maximum adsorption force of five 15 mm thick Halbach magnetic circuit magnets was 2 426.1 N. The magnet adsorption force of Halbach magnetic circuit could meet the requirement that the distance between the wall and the magnet was less than 5 mm, and the adsorption force was greater than 800 N, while the N-S positive and negative magnetic circuit could only meet the requirement that the distance between the wall and the magnet was less than 3 mm. Finally, the functional prototype of the robot was built, and the indoor vertical wall climbing and 1∶1 real ship model wall climbing tests were carried out. The research results show that the functional prototype of the robot meets the design requirements, and the robot can be safely attached to the wall, which lays the foundation for the next step of engineering prototype development.