The multi channel hydraulic system is widely used in industrial hydraulic systems. However, due to the difficulty in establishing an accurate mathematical model, its power control accuracy is poor and its response speed is slow. We calculate the estimated value of valve opening near the operation point by empirical formulas of the system. And then, the estimated value is adopted as the feedforward. In order to improve the accuracy and robustness of the system, the errors of the power of the system is allocated to suitable valves. Super Twisting Algorithm (STA) is used to construct a feedback loop to eliminate power errors and resist external interference. Finally, the control system is simulated by using Simulink and Amesim, and the fuzzy PID control is chosen as a comparison algorithm, the results indicate that STA has a good effect in accuracy and response speed issues.