In this paper, the 135 Degree of Freedom multi-body system dynamics model was built by using the software ADAMS/CAR, according to the requests of Chinese standards, and the simulating research about 6 performances of automotive controllability and stability were carried on. Based on the simulating results, some automobile’s performance, such as return-ability, slalom-ability and steering efforts-ability, were excellent, but some other performances, such as steady state cornering ability, steering wheel angle pulse input response ability and steering wheel angle step input response ability, were not satisfied. In order to improve the performance of the automobile, three parameters, i.e. the automotive mass, the load of front axis and the torsion stiffness of rear stabilizer anti-roll bar, were selected as the optimized objects. Within the variety range of the parameters, the multi-body system of the automobile was optimized. Automotive controllability and stability is improved obviously based on the simulating results of the optimized multibody system.