In view of the model uncertainty of the initial flight stage and the existence of external interference, a sliding mode control system based on feedback-linearization is proposed to solve the problem of attitude control in the initial flight stage of Guided Rocket. Firstly, the motion quaternion of Guided Rocket is established. Secondly, the feedback-linearization method is used to decouple the nonlinear system, and a nonlinear robust controller is designed by combining the idea of bounded disturbance with sliding mode control. Then, the disturbance boundary function and controller parameters are designed to realize the attitude stabilization control of the initial stage of air defense rocket. Finally, the stability of the system is proved through lyapunov theory. The result indicates that the control system based on feedback linearization method and sliding mode technique could ensure attitude stabilization of Guided Rocket and robust when great change of aerodynamic parameters and external interference exists.