Using the PHOENICS software with CAD, the 3-dimensional airflow around a car is numerically simulated, the wake flow is discussed in detail. The results show that due to the complexity of the body shape and the interaction of the ground, the external flow is very complicated and shows well-developed turbulence. In the wake area, because of the appearance of flow separation and towing vortices, and the formation of the horseshoe vortices, the drag is in general increased.