In view of the steel pipeline wall inspection work mainly relies on manual hand-held inspection equipment,a four-wheel drive magnetic particle inspection wall-climbing robot was designed.The static analysis of the robot under two dangerous conditions were carried out,and the minimum adsorption force of the permanent magnet wheel was 250 N.The size optimization model of the permanent magnet wheel was established and it was imported into the finite element analysis software Ansoft Maxwell,and the thickness and radius of the permanent magnet wheel yoke were optimized to be 6 mm and 20 mm.The magnetic field of the permanent magnet wheel was analyzed and the influence of the thickness and radius of the yoke on the adsorption force was studied;a robot prototype was assembled for experiments.The results show that the designed robot can walk and turn stably along the wall,which verifies the rationality of the robot design.