Considering the facts that the mechanization level of seed-grain sowing is low and that in practice thinning after seedling emergence demands a large amount of labor, pneumatic precision metering device was used to realize the purpose of the little precision seeding and the moderate reseeding of seed-grain. The physical and mechanical characteristics parameters of seed-grain were analyzed and determined and the effects of the structure of type holes, negative pressure, and rotating speed on sucking and metering performance of the metering device were observed. The results indicated that straight hole or the taper hole, all could achieve moderate resucking and the moderate resucking effect of taper hole whose diameter and taper were respectively 1.2 mm and 30° was the best. The stability variability coefficient of sucking was less than 5.47%, when the positive pressure was 200 Pa, the negative pressure 1 800 Pa, and the rotating speed 20 r/min. The number of qualified sowing hole was 95.7, the number of over sowing hole was below 11, the variability coefficient of seed quantity was 6.98%, and the seed quantity of each hole ranged from 1 to 6, when the positive pressure was 200 Pa, the negative pressure 2 200 Pa, and the rotating speed 24 r/min. The germination experiment revealed that the germination rate of seeds thrown by the metering device was above 93%, which showed no significant difference with that of untreated seeds. It concluded that the pneumatic precision metering device could be used in the actual planting of seed-grain.