A simulation model with multi-body dynamics and electronic power steering (EPS) was presented based on the co-simulation technology. First, by using automatic dynamic analysis of mechanical systems (ADAMS) software, a multi-body dynamic model of a full vehicle was established, then a PID controller was designed for the EPS under Matlab/Simulink environment; in addition, a data exchange interface with ADAMS/CAR was also defined. At last, a proposed control system including a multi-body vehicle model and a PID controller was implemented by using I/O interface under Matlab/Simulink and ADAMS environment, and the co-simulations have been carried out. The vehicle dynamic response under various operating condition was given. The results showed that co-simulation is effective and it could be applied in the development of vehicle engineering.