Abstract: By conducting large eddy simulation on a mini-bus, a new drag reduction method was proposed on the basis of trailing vortex control by exhaust emissions. Firstly, the accuracy of the simulation method was validated by comparing its results with the wind tunnel test data. Then the affect mechanism of the trailing vortex on the aerodynamic drag was analyzed by transient calculation, and the feasibility of the trailing vortex control based on exhaust emissions was analyzed. Finally, the influence of the different locations of exhaust pipes was investigated on drag reduction. A method was proposed to reduce drag by the exhaust of pulse emission, and the influence of different exhaust period of emissions was investigated on drag reduction. The drag reduction mechanism was comparatively analyzed for steady emission and pulse emission of the exhaust. The result shows that the condition in consideration of emissions provides great benefit in aero-drag reduction. The arrangement with a certain position has the maximal effect on aero-drag reduction up to 3.64%. Regarding the effect of drag reduction, the exhaust of pulse emission is more effective than steady emission. When the exhaust period is 0.08s, the optimal drag reduction effect is up to 4.76%.