Aim at modeling of valvecontrolled hydraulic cylinder,the characteristics of existing research results were analyzed.Linearization approximation is needed in the existing modeling process,at the same time,the definitions of load pressure and load flow are various,although eventually a unified transfer function can be established,the coefficient uncertainties of transfer function are large,and this will directly affect the application with high precision.From the view of engineering field,the concepts of load pressure and load flow were redefined,the transfer functions of symmetrical valvecontrolled asymmetrical hydraulic cylinder in two directions were derived,and further analysis was made.This research made reference for high precision application of electrohydraulic proportional symmetric valvecontrolled asymmetric hydraulic cylinder system.