This paper proposes a new type of spherical wheeled robot with an annular support leg. It can keep statically stable when powered off and automatically stand up with the assistance of the support leg when powered on. The stability of the robot at equilibrium is verified firstly using the planar simplified model. And the robot is proved to be controllable. Thus a double-closed loop control system is designed to stabilize the robot. Based on it, the standing-up control system and ramp-climbing control system are realized by changing control structure and using fuzzy control strategies. The design of the annular support leg, the experimental results and conclusions are also described in this paper.