Abstract: In order to discuss the performance of the metering mechanism and its action on different seeds, seeds of Medicago sativa, Elymus dahuricus and corn were chosen as testing seeds for their typical plants in China. The experiments for sowing Medicago stiva seeds, Elymus dahuricus seeds and corn seeds were accomplished. It was found that the performance of the metering mechanism met the requirements. The results also indicated that the input air velocity and seed feeding rate had influenced and V observably. The correlation coefficient was about 0.97. Finally, through optimizing the experimental scheme, the optimal air velocity and input seeds velocity were obtained. The Elymus seed’s air input velocity is 27～30 m/s and seed feed rate is 470～500 g/min. The Lucerne seed’s air input velocity is 30～33 m/s and seed feed rate is 505～ 520 g/min. The Maize seed’s air input velocity is 32～35 m/s and seed feed rate is 520～550 g/min.