Aiming at the problem of poor uniformity and stability of fertilizer discharge caused by the operation of the fertilizer discharger in the variable fertilization operation of rice. Combined with the agronomic requirements of deep fertilization on the northeast side, an impeller type variable side deep fertilizer was designed. According to the change of the prescription map, change the adjustment factors to achieve reasonable fertilization. Based on EDEM simulation, using the fertilizer discharge stability and uniformity coefficient of variation as indicators, under different impeller blades, different impeller speeds and different fertilizer discharge port angles, a secondary orthogonal rotation combination test was carried out, using Design-Expert. V8.0.6.1 is analyzed and tested, the regression equation and the response surface diagram are obtained, the interaction between the influencing factors is analyzed, and the best combination is determined. It is concluded that the stability and uniformity coefficient of variation of fertilizer discharge have reached the quality evaluation index of fertilization machinery According to technical specifications, the coefficient of variation of stability is 0.67%~2.85%, and the coefficient of variation of uniformity is 2.7%~16.4%. When the number of blades is 6, the fan angle of the fertilizer outlet is 35.7°, and the impeller speed is 18.85 r·min-1, the minimum variation coefficient of stability is 0.67%, and the minimum variation coefficient of uniformity is 2.1%. The bench test results are basically consistent with the optimal combination of simulation, and meet the design requirements.