An improved sliding mode control algorithm is applied to aeroengine control, for which the controller is designed that based on sliding mode control. An improved multi power reaching law of sliding mode control is proposed in this paper, which aims at reducing high frequency oscillation phenomenon appeared in multi power tracking control process of aero engine. The proposed reaching law is used in simulation of aero engine control system, whose results show that the proposed reaching law is applicable for tracking control of aero engine. Not only does the proposed reaching law has these advantages that are fast response speed and strong robustness but also it can eliminate high frequency oscillation phenomenon.