Aiming at the problem that the nonlinear characteristics of linear actuators in electromagnetic active suspensions affect the vehicle’s damping performance, the Maxwell stress tensor method was used to establish a nonlinear analytical model of input current and output electromagnetic force. By simulating the nonlinear force of the actuator, the problem of multiple structural parameters in the analytical model was reduced to two dimensions, and then the actuator fitting model was applied to the 1/4 vehicle suspension model by using the LQG controller, the impact of the nonlinearity of the actuator on the vibration damping performance of the vehicle was studied. The results show that the nonlinearity of the actuator makes the LQG control effect worse, and the actual damping performance decreases;when the ratio of the number of pole pairs to the length of the primary stator in the structural parameters of the actuator is close to the vehicle resonance frequency, the vibration damping performance is the worst.