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To explore the change rule of paddy layer ventilation resistance, guiding the tube network of ventilation drying warehouse design and fan selection, a numerical model of two varieties of paddy was constructed based on discrete element theory. The changing regulation of ventilation resistance of paddy at a series of wind velocities and paddy layer depths in a vertical tube was simulated by the coupled CFD-DEM model. The results showed that, when the apparent wind speed was constant, the resistance of paddy layer showed nonlinear increasing (R2>0.99) relationship with the increase paddy layer depth; when paddy layer depth was constant, the resistance of paddy layer showed a quadratic nonlinear increasing (R2>0.98) relationship with the increase of the apparent wind speed. Different varieties of paddy were under the same condition, and the layer resistance had the same change trend, but the numerical values was different, the ventilation resistance of long grain type was smaller than short grain type. By building test equipment, the simulation results of the experimental verification, paired t test results showed no significant difference was found, and the numerical simulation and experimental results agreed. The results testified that the numerical simulation of ventilation resistance in paddy was feasible by the method of CFD-DEM. The fitting equation obtained can be used for calculating barn ventilation resistance and guiding the tube network of instore drying system design, fan selection, paddy ventilation resistance simulation and engineering practice.In the design and operation on barn drying system, the apparent wind speed is appropriate at 0.2~0.3 m/s, paddy layer depth is not more than 1.5 m, the difference of grain type should be considered when calculating the ventilation resistance.