In order to study the aerodynamic drag reduction effect of the plasma on kind of vans, ground transportation system（GTS） model was taken as the research object. Numerical simulation was used to investigate the aerodynamic drag reduction effect of plasma arrangement angle and excitation voltage at three positions on the GTS model when the incoming wind speed was 20 m/s，and the drag reduction mechanism was analyzed. Then, the combined working conditions were analyzed. The results show that plasma can make the separation point of the flow move back and delay the separation of the flow by inducing the directional flow of gas near the wall, so as to reduce the pressure difference between the front and rear of the GTS model and reduce the aerodynamic drag coefficient of the vehicle. Moreover, plasma should be set behind and close to the flow separation point. The aerodynamic drag reduction effect is the best when plasma is applied to both sides of the tail of GTS at a single position, and the maximum drag reduction rate is 5.09%. The maximum drag reduction rate can reach 6.01% under combined condition. When the incoming wind velocity is constant, the plasma has the optimal arrangement angle and excitation voltage.