The electrohydraulic servo type road simulator is one of the most significant method of developing and verifying the fatigue and endurance for both vehicle and it’s structures.The framework and principle of the electrohydraulic servo system of the road simulator were analyzed synthetically.The mathematic formulas of key component in system were inferred,which consisted of valvecontrol symmetry hydraulic cylinder,electrohydraulic servo valve,servo amplifier,etc.The system mathematic model was established.After using AMESim to model the simulation model about electrohydraulic position servo system,typical signals were used for simulation analysis,and the electrohydraulic servo type simulator from American MTS was used for simulation verifying.The step respond characteristic,frequency respond characteristic,the load stiffness characteristic,and the influence factors of these characteristics were analyzed based on the validated high accurate model in detail.It provide reference for developing electrohydraulic servocontrol system.