Abstract: To improving the estimate accuracy of pressure of electro-hydraulic braking (EHB) system, a novel dynamics modeling method was proposed based on particle swarm optimization and unscented Kalman filter (UKF) arithmetic. In the arithmetic, according to the work characteristic of EHB system, the pressure estimation was translated into optimizing multidimensional parameter. The nonlinear differential equations were derived in terms of dynamic characteristics of electro-hydraulic braking system. Then, the UKF was applied to estimate the time-varying parameters of the model with an objective function. To obtain accurately the time-varying parameters, the measurement noise, process noise, and parameters in the unscented Kalman filter were optimized with the particle swarm algorithm. Comparing with the experimental data in several braking cases, the results validate the effectiveness and accuracy of the novel method. Therefore, the proposed model can not only provide a theoretical basis for the design of a hydraulic braking system but also help realize the chassis integrated control of electric vehicles.