Precision fertilization is a high-efficiency fertilization method, and the fertilizer ejector is a key link in precision fertilization. In order to realize the precise fertilizer discharge of the fertilizer ejector, the fertilizer discharge performance of the arc-groove double-screw fertilizer discharge device based on the principle of dislocation superposition single screw fertilizer discharge curve was analyzed, the factors affecting its fertilizer discharge performance were obtained, and the factors affecting the fertilizer discharge uniformity of the arc-groove double-spiral fertilizer discharge device were obtained, taking the pitch S, arc-groove radius Rp and center distance a as the test factors, and taking the uniformity variation coefficient and fertilization accuracy as the test indexes, the three-factor and three-level Box-Behnken test was carried out. The optimal parameters were pitch S=35mm, arc-groove radius Rp=17.5mm and center distance a=35mm. The arc-groove double-spiral fertilizer discharge device was made under the optimal parameter combination, and the bench verification test and comparative test were carried out. The test results showed that the uniformity variation coefficient of bench test and the relative error between fertilization accuracy and simulation test were 5.07% and 4.69%, respectively, and there was little difference between them, which verified the correctness of simulation. The uniformity variation coefficient of the optimized arc-groove double-spiral fertilizer discharge device was 7.26 and 15.48 percentage points lower than that of the non optimized arc-groove double-spiral fertilizer discharge device and single spiral fertilizer discharge device respectively. The optimized arc-groove double-spiral fertilizer discharge device had good fertilizer uniformity and effectively solved the problem of uneven fertilizer discharge of the single helix fertilizer ejector, it can provide a reference for the structural improvement and optimization of arc-groove double spiral fertilizer ejector.