Abstract: To enhance the movement flexibility and practicability of the hopping robot, a two-wheel robot with hopping ability is designed by combining hopping movement and wheeled movement. The hopping movement is realized by a threebar spring model of hopping mechanism which can reduce the body size and enhance the energy utilization at the same time. The structure constitution and principle of the robot are introduced in detail. Then, dynamic models of the robot during the hopping motion period are built, the factors affecting hopping ability of the robot are analyzed. To verify the validity of the mechanical design, wheeled motion and hopping motion during robot obstacle-crossing are simulated with ADAMS. The control system and a principle prototype of the two-wheel robot are developed. Finally, hopping experiment results show the reasonability of robot design and the validity of theoretical analysis. For this hopping robot, the energy utilization is close to 70% and the jumping height is greater than its own size.