Objective In response to the drying quality problem caused by the uneven distribution of the flow field inside the tunnel-type dryer for Lyophyllum decastes, this paper proposes a structural optimization method based on the porous media model, aiming at improving the drying uniformity and energy efficiency.Methods The viscous drag coefficient and inertial drag coefficient of L. decastes are measured, and the Realizable k-ε turbulence-porous medium coupling model is established. A double-end flow equalizing plate deflector is designed and used to optimize the airflow distribution based on a hexagonal close-packed hole array, and the optimal parameters are screened by combining the analysis of pressure drop characteristics for five aperture schemes.Results After optimization, the average velocity of YZ, XZ, and XY sections are increased by 48%, 25%, and 26%, respectively, and the nonuniformity coefficient of air velocity is reduced by 62%, 48%, and 49%, respectively. Experimental verification shows that the standard deviation of drying uniformity index is reduced by 67.5%, and the energy efficiency is increased by 30.1%. As a result, the drying cycle is shortened by 19%.Conclusion The dual mechanism of flow field shaping by the aperture of the flow equalizing plate is obtained in this study: narrow apertures accelerate the airflow to suppress flow separation, while periodic aperture arrays balance the velocity distribution.