A co-rotating and double-spiral fertilizer feeder with a double distributing wheel was designed to solve the problem of uneven fertilization， resulting in low utilization efficiency of fertilizer in traditional fertilizer feeder. The theoretical discharge capacity of fertilizer and the parameters affecting the uniformity of fertilizer were determined through theoretical analyses. A Box-Behnken experiment with three-factor and three-level was conducted using the pitch， center distance， and blade height of the fertilizer distributing wheel as experimental factors， and the fluctuation coefficient of fertilizer uniformity and average axial speed as experimental indexes. The results showed that the effect of pitch on the fluctuation coefficient of fertilizer uniformity was extremely significant （P<0.01）， while the effect of center distance and blade height on the fluctuation coefficient of fertilizer uniformity was significant （0.01<P<0.05）. The effect of pitch， center distance， and blade height on the average axial speed was extremely significant. When the center distance， the pitch and the blade height of the fertilizer distributing wheel was 48 mm， 32.5-33.2 mm and 13.5-14.7 mm， the fluctuation coefficient of fertilizer uniformity was ≤10%， and the axial speed of the fertilizer was ≥30 mm/s， the optimal performance of the fertilizer feeder was achieved. Under the optimized parameter combination， the relative error between the fluctuation coefficient of fertilizer uniformity in the bench experiment and simulation experiment was 1.47%， and the relative error between the volume of fertilizer distributed in a single lap in the bench experiment and simulation experiment was 1.96%， indicating that the bench experiment and simulation experiment are in good agreement. At different speeds， the fluctuation coefficient of fertilizer uniformity in the co-rotating and double-spiral fertilizer feeder was reduced by an average of 64.21% and the average fertilizer volume distributed in a single turn was increased by 72.16% compared to the single-spiral fertilizer feeder， indicating that the optimized the co-rotating and double-spiral fertilizer feeder has good fertilizer uniformity and a large flow rate of fertilizer. It will provide a useful guide for designing a co-rotating double-spiral fertilizer feeder.