A crawler wall climbing robot with electromagnetic adsorption is designed, which can remove rust and recover sand grains at high altitude for typical steel structures of power plants such as narrow columns and crossbeams. The static model and dynamic model of the wall climbing robot climbing along the steel structure wall were established to deduce the starting and working torques of motors for the robot climbing up wall, and to provide theoretic basis for selection of electromagnets and motors. The relationship between the adsorption force and the static friction coefficient and the inclination angle of the steel structure wall was obtained by using MATLAB simulation and computation.The influence of the pendulum angle of swing arm and the inclination angle of the wall on the adsorption force was discussed when the robot did not overturn. The analysis results show that when the inclination angle of the steel structure wall is 21.8 degrees and the static friction coefficient is 0.4, the maximum magnetic adsorption force required by the robot is obtained. When the number of single-side crawler electromagnets is 20 pieces, the selected and installed electromagnet with adsorption force must be greater than 54.37 N to avoid the robot sliding down or overturning along the steel structure wall so as to ensure its climbing safety.