In the earlier stage, a stepped vibrating seed sowing mechanism in the seed supply link of the precutting cassava seeder was designed. In order to further realize the precision seeding of cassava seed stems, a seed sowing mechanism was designed behind the stepped vibrating seed sowing mechanism to complete reliable seed filling and precision seeding. However, it was blind to take a single kind of stem from the cassava seed stem group that had been adjusted and sequenced through the seed metering mechanism scoop, which was easy to cause problems such as missing filling and reseeding. The spoon chain seed metering mechanism was further designed to solve the problems of seed filling difficulty and low seeding qualification index of the current precutting cassava precision seeder. The working principle of the seeder and the parameters related to the design of the spoon chain metering mechanism were described. Based on the theory of the fastest descent line, the parameters of the seed scoops of the metering mechanism were designed. The forces on the cassava seed stems and the motion state during the seed filling and seed feeding process of the mechanism were theoretically analyzed. It was determined that the significant factors affecting the seed filling performance were the type of seed scoops, the number of seed scoops, the motion speed of the conveyor chain, and the seed filling angle. Single factor simulation was carried out by using EDEM software, and the influence rules of different test factors on seed filling performance were obtained. The response surface BBD simulation test was carried out to determine the optimal factor parameter combination. The prototype seeder was developed for bench and field tests. The results showed that when the seed filling angle was 37°, the number of seed scoops was 12, and the moving speed of the conveyor chain was 0.63m/s, the qualified index of seed filling was 93.8%, and the missed filling index was 1.9%. The field experiment showed that the spoon chain seed metering mechanism of the precut seed vibrating seed feeding cassava seeder had better performance and it can meet the agronomic requirements of precision cassava sowing.