In order to solve the problem that peanut seed filling effect is poor under the condition of high speed operation in the process of peanut planting to precision and high speed, a kind of pneumatic assisted seed-filling precision seed metering device was designed, specially, the structures of planter plate and pneumatic assisted seed-filling device were mainly designed. For peanut seeds with large particle size and mass, by analyzing the phenomenon of peanut seed accumulation in the seed metering device and the filling time, it was concluded that the peanut high-speed seed discharging and filling process needed to enhance the filling performance, so as to improve the filling efficiency. Through analyzing the principle of peanut seed filling, the relationship between the movement and force of seeds and seed metering device in the seed filling process of peanut seeds was clarified, and the influencing factors of the seedfilling process were analyzed. The key structural parameters of the seed suction holes and seed guide slot of the seed metering device and the parameters and arrangement of the auxiliary seed blowing holes were analyzed and calculated by designing the seed metering device with seed guide slot and the auxiliary seed filling structure with auxiliary seed guide holes. Taking the qualified rate of seed filling and the leakage rate of seed filling as indexes, a three-factor and three-level combination test was carried out, and the test results were subjected to multivariate regression analysis to optimize with the optimal objective, and the optimal parameter combinations of seed planter plate were determined to be the negative pressure of seed suction in the seed metering device of 5.156kPa, the forward speed of the high-speed planter for peanut was 8.007km/h, and the positive pressure of disturbed blowing of seeds was 1.149kPa. In this case, the qualified rate of peanut seed filling was 95.84%, and the leakage rate of peanut seed filling was 4.06%, which could realize the effective seed filling of peanut seeds.