Abstract: In view of the complicated structure of the Hybrid Electric Vehicle(HEV), a two-axle driving system is proposed. A traction coupled-HEV drive system for the vehicle is designed, making it a two-axle drive HEV. The vehicle can simply switch the operating modes. A two-axle drive HEV model is established with the aid of AVL-Cruise, and its performance indices, such as the maximum gradient, the acceleration time, the power and the fuel consumption, and the distribution of the engine's operating points, are obtained by simulation tests. The results show that the traction coupled-HEV drive system allows the engine and the motor work efficiently. Therefore, the fuel efficiency is improved, and the advantages in energy saving and emission reduction are significant.