Abstract: To achieve variable fertilization and improve the uniformity and accuracy of fertilization, an electrically controlled fertilizer discharging device was designed. The device can automatically adjust the speed of the outer grooved wheel according to the operating speed of the tractor, target fertilizing amount, and the effective working length of the outer grooved wheel. The experimental platform of the electrically controlled fertilizer discharging device is built to calibrate the system parameters. The functional relationship between the effective working length of the outer grooved wheel fertilizer discharge device and the average fertilizer discharge per revolution is obtained by experiments. The fertilizer discharge stability is better in the range of 20～40 r/min. The field experiment results showed that the coefficient of variation of fertilizer discharge was less than 1.72% in the range of 25～40 r/min, and the uniformity of fertilizer discharge was good. When the target fertilization amount was 150, 200, and 250 kg/hm~2, the deviation between the actual fertilization amount and the target fertilization amount was less than 7.68%. It can provide a reference for precision fertilization technology.