In order to solve the problems of low applicability of seed metering device, low quality of seeding operation and low production efficiency existing in the current seeding methods of green manure, a trough-hole combined type multi-variety green manure quantitative electric evenly-sowed mechanism was developed, the key components such as the pyramid seed box, the trough-hole combined type seed metering device and quantitative electric evenly-sowed components were designed. The sliding friction angles of the eight main green manure varieties were measured, and the minimum inclined surface angle of the designed pyramid seed box was 35.5°, on the basis of the seed size, totally 1000 grain weight and seed consumption of per unit area, the seeding channel of the trough-hole combined type seed metering device could be selected and the effective opening of the channel could be set as well, by using EDEM software, the simulation model of the evenly-sowed mechanism was built, and it was verified that the probability distribution of the seed fallen on the ground after colliding with the cylinder was quite consistent when the diameter of cylinder was ranged from 3.2mm to 6.8mm. Qingyijiang NO.1 was used as the test material, the multiple factor experiments, as well as regression analysis of the test data were carried out, the results showed that among the three factors in the experiment, the rotation speed of sowing wheel had the greatest influence on the emergence rate and uniformity variation coefficient of sowing, while the forward speed of machine had the least influence on the emergence rate and variation coefficient of sowing uniformity, regarding the stability variation coefficient of each row sowing quantity, the most influential factor was the even-distributed cylinder diameter, and the minimum impact factor was the rotation speed of sowing wheel, the optimal factor parameters combination which affected the sowing quality of the trough-hole combined type multi-variety green manure quantitative electric evenly-sowed mechanism was as follows: machine forward speed was 3.36km/h, rotation speed of sowing wheel was 44r/min,even-distributed cylinder diameter was 6.14mm. Verified by field experiments, the Astragalus smicus emergence rate was 96.49%, consistency variation coefficient of each row sowing quantity was 11.73%, variation coefficient of sowing uniformity was 8.67% in the condition of the optimal parameter combination, the relative error was below 6% compared with optimal values predicted by the model, which validated the optimal values of the three factors. Compared with the existing methods of sowing Astragalus smicus seeds, the designed trough-hole combined type multi-variety green manure quantitative electric evenly-sowed mechanism had a work efficiency of 0.8hm2/h to 1.0hm2/h, which was superior to the artificial sowing efficiency of 0.1hm2/h to 0.125hm2/h, the hand-shaking efficiency of 0.2hm2/h to 0.3hm2/h and the motorized sowing efficiency of 0.5hm2/h to 0.8hm2/h, which was lower than the UAV sowing efficiency of 3hm2/h to 4hm2/h. In addition, the seeding quality was also significantly superior to that of other methods, which had a good prospect for application.