According to the requirements of high performance and high efficiency for hydraulic cylinder control systems with heavy load and longstroke in many application fields,such as hydraulic ship lift,multiple degree of freedom test platform etc,the unsymmetrical hydraulic cylinder system parallel driven by valve control open circuit and pump control closed circuit is adopted.The system can acquire high performance and high efficiency,but need maintain performance.In order to suppress electromagnetic disturbance problem of speed and displacement sensors,antidisturbance observer strategy based on the PID position feedback control was proposed,and the control performance of the system was verified by simulation.The simulation results show that compared with traditional PID control strategy,the method can be used to accurately estimate the sinusoidal disturbance and compensate it in the feedforward channel.It can also be used to eliminate the influence of single sinusoidal disturbance with known frequency,so the system can follow given signal quickly.