The effects of nonlinear factors in electric servo mechanism, such as transmission clearance, rigidity and friction were analyzed. Aiming at the electric hydraulic servo actuator of air vehicle as a research object, the simulation model was established based on LMS Imagine Lab AMESim one dimensional multi-field system simulation integration platform, to accordingly analyze with simulation the effects of nonlinear factors in the performance of system, such as transmission clearance, friction and stiffness of the mechanism. The obtained results provide a theoretical support for the optimum design and performance forecast of the electric hydraulic servo control system of air vehicle.