In response to the problem of large differences in size of three axes of maize seeds, which are prone to omission and re-taking during seed picking, a swing-clamp type maize precision seedmetering device was designed, its structure and working principle were introduced and analyzed, and the key components were designed. The key factors affecting the seed extraction performance of the seed-metering device were obtained by establishing mechanical and kinematic models for analysis. The simulation model was established by EDEM software to further analyze the influence law of population height and seed-metering device's rotational speed on population flow speed, and the seed-metering device's fetching performance curve was obtained. The seed picking block opening and closing angle, seed feeding cylinder installation height and seed-metering device's rotation speed were used as experimental factors, and the single seed picking rate, leakage rate and multiple picking rate were used as evaluation indexes for the secondary orthogonal rotation combination simulation test, the results showed that the optimal combination of parameters was 43.87°of seed picking block opening and closing angle, 37.84mm of seed feeding cylinder installation height and 0.41r/s of seed-metering device's rotational speed. Under the optimal combination of parameters, the seed row performance bench validation test was conducted, and the seed row qualification index of the seed rower was 94.11%, the missed seed index was 2.52% and the reseeding index was 3.37%, meeting the industry standard and agronomic requirements. The research result provided a theoretical reference for the design optimization of different working area components of the mechanical corn precision seed-metering device.