In order to simplify the structure of seeding monomer, improve the quality of planting, and meet the agricultural requirements of narrow row of soy closely planting on planter, a centralized belt type soybean seed-metering device was designed. The method of circulating flow seed filling and vibrating seed cleaning of the seed-metering device was described. The key structural parameters, such as supporting wheel, vibration bench for clearing seed, seed conveyor belt, position of air inlet and sealing device were determined through theoretical analysis and simulation analysis. The mechanical model of seed filling process and seed cleaning process was established, and the basic structure and working principle of the seed-metering device were introduced. The experiment was employed through the method of quadratic orthogonal rotating center combination of three factors and five levels according to national standard (GB 6973—2005). In test, soybean seed Heinong 38 was selected as experimental material. Combining with extensive pre-experiment and theoretical analysis, the air pressure, working speed and clear vibration frequency were taken as the main influencing factors, and seed qualified index, multiple index and missing index were taken as the response index, the experimental research was carried out. The optimal combination of parameters were clear vibration frequency of 44.6Hz, air pressure value of 4.4kPa and working speed of 10.5km/h, and under the optimal combinations, the qualified index was 90.65%, the multiple index was 1.97%, and the missing index was 7.38%, the verification test was repeated five times, the results indicated that the actual test results were in agreement with the optimization results. This seed-metering device could meet the seeding requirements well. The research results provided a reference for the research of centralized precision seed-meter device.