The electro-hydraulic system is one of the most important parts of automatic transmission.It mainly includes solenoid valve,shift valve and clutch which,involving in electronic,mechanical,and hydraulic fields.The accuracy of clutch pressure control can be improved by analyzing the dynamic characteristics of this the electro-hydraulic system.Through modeling and simulation analysis,the characteristic curves of current and pressure were obtained.Simultaneously,the effect of pressure hysteresis was found.After analyzing the reason of pressure hysteresis,the dither current control of solenoid value was put forward,and the principle of dither current control was introduced.Finally,the result that the dither current control can reduce the effect of pressure hysteresis is verified by the pressure hysteresis test.It means the dither current control can improve the accuracy of pressure control.