The aerodynamic performance of an automobile is affected by differing automobile tail shapes. Different simple automobile models were designed and analyzed with the FLUENT software; by using this research method, one can qualitatively analyze the automobile flow field, as well as the lift and drag coefficients in an accurate manner. The results from an analysis of different automobile tails indicate that the most improved automobile model tail shape resulted in a drag coefficient of 4.5% lower than the basic model, and a lift coefficient of 41.6% lower than the basic model. This design had the smallest drag coefficient, the smallest lift coefficient, and the best aerodynamic performance when simulated in the FLUENT Software, allowing the user access to a tangible reference basis for choosing an automobile model.