Abstract: To address issues such as clogging and uniformity of fertilizer discharge during high-speed operation in spiral fertilizer device used with corn planter, a pneumatic-assisted spiral fertilizer device was designed to create a synergistic fertilizer discharge mechanism combining gravity feeding, spiral propulsion, and pneumatic transportation．Bench tests were conducted to investigate effects of spiral pitch, spiral conveyor rotational speed, and airflow velocity on fertilizer discharge performance, and Box–Behnken design method was employed to optimize key parameters．Results have shown that each factor had a significant effect on both fertilizer discharge rate and discharge uniformity, and established quadratic regression model exhibited a high degree of accuracy．Optimal parameter combination was a spiral pitch of 31 mm, rotational speed of 120 r/min, and airflow velocity of 30 m/s with a fertilizer discharge rate of 90.1 g/s and coefficient of variation of 3.9%, meeting requirements for precision fertilization．Theoretical support for structural optimization and parameter matching of pneumatic-assisted fertilizer device for corn planters has been provided by these research findings．