The coupled simulation of gas-solid two-phase flow was widely used in the study of the working process of pneumatic seed metering devices, the seed model was mostly modeled by particle aggregation formed through particle aggregation without overlapping. The simulation seed model would be closer to the real shape of the seed with smaller radius and larger number of filled spherical particles by this method. But the simulation computing resources would be overconsumed and the simulation time would be increased as the method was used. The rice seeds were taken as research object in order to study the effect of rice seed models with different filling sphere radii on the dynamic response characteristics between particles and find the optimal number of filled balls for the seed model. The bonding aggregation model of rice particles for gas-solid coupling was formed by filling with spherical particles of different radii (0.30mm, 0.21mm, 0.18mm, 0.16mm and 0.15mm) after the shape of the seed was got with the aid of 3D scanning and inverse fitting method. The static friction coefficient and dynamic friction coefficient of seed model filled with balls of different radii were calibrated by lifting with bottomless cylinder，sliding accumulation between real test and simulation, using the curve surface correspondence method and the index was the angle of repose. The results showed that the simulation time and simulation accuracy were the best when the filled particle radius was 0.21mm verified by the gas-solid two-phase flow coupling simulation test of the rice seed metering device with positive pressure as the indicator was seed filling rate.