Abstract: Dynamics of the four-wheel driving wall-climbing robot with sliding suction cups in skid-steering mode is studied.First,motion state and constraint of the robot working on wall surface safely are analyzed,then distribution of supporting forces acting on driving wheels,lateral friction force between driving wheel and wall surface,and friction force acting on sealskirt of suction cups are analyzed,and dynamic model of the robot is constructed based on the Newton-Euler method in the end.A safety factor of driving torques is established to denote the safety degree of driving torques.The influence of adhesion force,distribution of driving wheels and rigidity of sealskirt on driving torque is analyzed by dynamic simulation.As a result,it lays the theoretical foundation for mechanism optimization and safe motion control of the four-wheel driving wall-climbing robot with sliding suction cups.