Abstract: In order to meet the requirements of exploration operations in complex and unknown environments for mobile robots, a novel wheel-legged mobile robot is proposed by utilizing the high over-obstacle capacity of three-spoke wheel-leg mechanisms and the good damping capacity of arc-shaped wheel-leg mechanisms.Taking stairs-climbing as the over-obstacle task and design objective, the non-slip condition between the robot wheel-leg and the stairs is analyzed from the perspective of statics, and then the necessary condition of the novel robot climbing the stairs is obtained.A trajectory for climbing stairs efficiently is designed from the perspective of geometry, and then the parameters of the robot wheel-leg are obtained before investigating the influence of the wheel-leg parameters on the impact resistance and endurance abilities.Finally, the software simulation and stairs-climbing experiment are carried out to verify the validity of the presented research.