Considering the problem that the wheat seeds have poor fluidity in the seed filling link of the seed feeding device of air-assisted centralized metering device for wheat, which leads to unstable seed filling and feeding, a seed feeding device with constant width polygon groove-tooth wheel for wheat was developed. The working principle of the seed feeding device was described. The main structural parameters of the constant width polygon groove-tooth wheel were determined. The effects of different structure types of groove-tooth wheel on seed population disturbance ability, seed filling and seed feeding performance were compared and analyzed by EDEM. The simulation results showed that when the rotating speed of the seed feeding shaft was 20r/min, with the increase of side quantity of the constant width polygon groove-tooth wheel, the average kinetic energy of the seed population was gradually decreased, and the average disturbance ability to the seed population was decreased in turn. Nevertheless, the interval between the adjacent average kinetic energy peaks was decreased and the frequency of disturbing the seed population was increased. The average kinetic energy of the seed population under the disturbance of the constant width triangular, the constant width pentagonal, the constant width heptagonal, and the constant width nonagon groove-tooth wheel was 371.32%, 209.23%, 91.02%, and 53.37% higher than that of circular groove-tooth wheel, respectively. Taking the quality rate of seed filling ((2±1) grain/hole) and missing rate of seed filling (0 grain/hole) as indicators, the quality rate of seed filling and missing rate of the constant width heptagonal groove-tooth wheel were 93.98% and 2.78%, respectively. The seed feeding quantity and seed feeding time had high linearity, and the seed filling and seed feeding performance were better. The bench test verified the seed feeding performance of the seed feeding device with the constant width heptagonal groove-tooth wheel and the effect of seed feeding device on seeding performance. The results showed that when the rotating speed was 10~60r/min, the variation coefficient of seed feeding rate stability was not higher than 2.14%, the damage rate was not higher than 0.20% during feeding process, the variation coefficient of total seeding mass stability was not higher than 2.15%, the damage rate was not higher than 0.23% during seeding process，which met the requirements of stable wheat seed feeding.