Abstract: A new air-ground amphibious vehicle based on quad rotor was proposed to meet the need of indoor reconnaissance. The control strategy of the vehicle was analyzed. Then the dynamics model of flight system was built. A Backstepping control design method based on Lyapunov stability theory was used to design the control law of each attitude of the system. Through simulation with Matlab software, the response curve of each attitude was obtained for the flight system. The analysis results show that the vehicle can complete the scheduled action, and prove the validity of the control laws.