In order to solve the difficulty of multi-wall transition in the cleaning process of ship cargo hold,a magnetic adsorption wall-climbing robot with adaptive ability to wall is designed in this paper, which includes magnetic adsorption mechanism, adaptive cleaning mechanism and walking mechanism. Firstly, a mechanical model of the robot in the process of wall transition is established to obtain the distribution characteristics of magnetic adsorption force and a magnetic adsorption mechanism is designed. Secondly, ANSYS Maxwell 3D software is used to optimize the distribution of magnetic adsorption force of the mechanism to meet the needs of wall transition. An adaptive cleaning mechanism is designed in the head of the robot, and the wall transition ability of the cleaning mechanism is verified by experiments. Finally, the robot prototype is tested according to the actual characteristics of cargo hold wall. Experiments show that the wall-climbing robot can complete the transition process between the bilge and the roof of the cargo hold, which verifies the robot’s ability to adapt to the wall and walk in the cabin.