A hardwareintheloop simulator used for the development of vehicle driver assistant systems was outlined. Based on analysis of dynamics of main vehicle components, a seven-degree-of-freedom non-linear vehicle dynamics model was built for the simulator. Modeling process for vehicle model with Matlab/Simulink and Stateflow was depicted in detail. Simulation and road tests have been conducted to evaluate the vehicle model. It is shown that the vehicle model has small demand for computation resources and good accuracy in terms of both longitudinal and lateral dynamics.