Considering nonlinear control problem of hydraulic erecting system and combining high order sliding mode control theory, a kind of high order sliding mode control method based on differential observer was proposed. An erecting angle tracking controller based on high order sliding mode control method was designed for erecting system. A differential observer was adopted to get the information of the erecting angle derivatives and sliding variable derivatives. An observer based control method was constructed. The experiment results show that the proposed method can be applied to real hydraulic erecting system. Compared to PID control and conventional SMC, the proposed method can effectively attenuated chattering and enhance the control performance.