In view of an improvement of the aerodynamic stability caused by aerodynamic lift at a high speed, an improved design method has been proposed of closing the bottom of front axle with an addition of the“front teeth” attachment device so as to achieve an excellent vehicle aerodynamic lift performance. Based on the accuracy of the algorithm verified by wind tunnel experiments, the optimal Latin hypercube method is used to design the sample points, with the Kriging proxy model adopted to construct the approximate model between the optimal design variables and the aerodynamic lift coefficient. Meanwhile, the multi-island Genetic Algorithm (Mga) is used for an optimization of the parameters of the automobile front tooth attachment. The results show that it is characterized with a high accuracy with the application of LBM to the calculation of vehicle aerodynamic lift; by closing the bottom near the front axle, the aerodynamic lift characteristics can be effectively improved, with the aerodynamic lift reduced by 36.4%; with a respective addition of 359.54 mm width and 27.46 mm of the height front teeth, the front axle lift coefficient Clf is maintained at -0.063 7, which meets the actual engineering requirements.