Abstract: Designing a distributor that ensures uniform porosity distribution in grain piles is of great significance in solving the serious problem of automatic grading in shallow cylindrical silo. First of all, Hefeng No. 55 soybean with a moisture content of 13.5% was used as the research object. On the basis of measuring the intrinsic parameters of real soybean particles, a non-spherical soybean particle model filled with four spheres was constructed, and the discrete element simulation parameters were optimized. Hertz-Mindlin was selected as the soybean particle contact model, and the deformation of the particle was ignored. The proportion of soybean particles, imperfect soybeans and soybean hulls in the grain pile was 0.84∶0.15∶0.1. Taking the porosity uniformity of grain piles, ventilation uniformity and cooling rate of grain piles as indicators, a distributor for shallow cylindrical silo with a diameter of 18.0 m and a height of 20.0 m were designed and optimized, and the speed of the distributor was set to 0, 5, 6 and 7 r/min. Forty monitoring points were evenly set up on each floor at the horizontal sections in the height direction Z=2.0, 4.0, 16.0, and 20.0 m to monitor the temperature. Then, the rationality of the Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) coupling method was verified. To reduce the cost and simplify the experiment, a small test shallow cylindrical silo 10 times smaller than the actual shallow cylindrical silo was designed for the ventilation experiment, and the ventilation and drying of grain piles were simulated. Finally, the parameters of ventilation uniformity and ventilation cooling velocity of the grain pile with different distributor structures were compared and analyzed, and the optimal distributor structure was determined. In the calculation of coupled ventilation, the Eulerian model was selected due to the obvious effects of soybean particles on the fluid. The results showed that, compared with the CFD calculation method, the CFD-DEM coupling calculation method could better reflect the airflow and heat transfer inside the grain pile under real ventilation conditions. When distributing soybeans in a shallow cylindrical silo with a diameter of 18.0 m and a height of 20.0 m, the application of the distributor could effectively avoid the extreme value of the porosity inside the grain pile. Meanwhile, it could significantly improve the ventilation uniformity and cooling rate of the grain pile. The best distribution and ventilation effects were achieved when the structure of the distributor had six arms and a speed of 6 RPM.