Abstract: A new method using the extended Kalman filter theory to measure indirectly the sideslip angle and yaw rate of vehicle was proposed.The Kalman filter theory and algorithms was studied，and a 2-degree of freedom dynamics observer model of vehicle was established based on the GIM tire model.By contrasting with high-precision vehicle model，the simulation results showed that the estimation method，which measure the state variables required by control system of vehicle with longitudinal and lateral acceleration，was a kind of high precision and low cost technology.It has great significance to promote use of active safety system in the middle and low cars.