In order to explore the influence of the structural parameters of air filter on the performance of engine air filter, the flow field inside the filter was simulated by using the lattice Boltzmann method and turbulence model method with ANSYS software. The porous medium model was used to replace the filter element part, and the pleats of the filter element and the inner and outer diameters of the filter element were used as the structural parameters.The effect of the structural parameters on the flow uniformity,flow resistance and service life of the air filter was emphasized. The results show that the air filter of a certain type of engine has the optimal filter pleats and inner and outer diameter. The overall performance of the optimized air filter is better than that of the original air filter. The improved air filter has small flow resistance, reduced swirl number and small speed impact, the air flow uniformity is increased.