In order to study the mechanism affecting the uniformity of seed supply in Venturi, DEM-CFD coupling simulation method was used to analyze the variation of fluid field, coupling field and particle field under different shrinkage angles, and the shrinkage angle of 70°was obtained, the pressure field of the flow field was changed obviously, the range of action was reasonable, the maize accumulation phenomenon did not appear in the coupled field, and the continuous uniform velocity of the seed field was consistent. In order to explore the effect of seed feeding volume and air blowing pressure on the uniformity of Venturi feeding tube, orthogonal experiment was carried out to measure the uniformity of seed supply for the variation coefficient of seed quantity. The range analysis of the test results showed that the primary and secondary factors affecting the uniformity were the quantity of feeding and the air blowing pressure. The variance analysis showed that the quantity of feeding was a very significant factor, and the air blowing pressure was a significant factor, and the interaction terms of the two were not significant factors. The test results were optimized to obtain the best uniformity when the quantity of feeding was 1.8kg/min and the air blow pressure was 7kPa. The seeding performance test was carried out on the above combination when the seed meter rotation speed was 136r/min. The qualified index was 92.18%, the leakage index was 0, and the multiple index was 7.82%. The results showed that no leakage can explain the combination was the best. Under this circumstance, the performance of Venturi feeding tube was uniform, which was basically consistent with the theoretical optimization results.