Taking the valve controlled asymmetric cylinder system as the research object, in order to obtain the accurate model of the system and improve the position control accuracy, the system was identified.Aiming at the nonlinearity and asymmetry of hydraulic cylinder, a position control method based on position reference and position closed-loop dual PID was proposed.The mathematical model of the valve controlled cylinder system was established; based on Rexroth hydraulic experimental platform and NI measurement and control system, the valve controlled cylinder system was identified in time domain and frequency domain respectively, and the accurate mathematical model of the system was obtained.Based on the mathematical model, the system characteristics were analyzed.The designed position control strategy of valve controlled asymmetric cylinder was verified by experiments.The results show that the system can achieve more accurate position control under the stability margin.