Considering at the problem that the narrow-row close planting, high sowing uniformity and lack of suitable sowing technology and equipment for small-size vegetable seeds such as spinach, a pneumatic needle planetary gear train multi-row parallel low-drop precision metering device suitable for close planting precision sowing of small-size vegetable seeds such as spinach was designed. The working principle of seed metering device was expounded, and the seed mechanical models of seed suction and seed feeding were constructed, and the main structural parameters of seed metering device were determined. ADAMS software was used to simulate and analyze the static trajectory and dynamic trajectory of the suction needle of the planetary gear train seeding mechanism, and the low zero-speed seeding conditions were clarified. The performance test of seed metering device was carried out. The results of seed-metering test showed that the primary and secondary order of affecting the qualified index was rotation speed of seeding, suction negative pressure and unloading positive pressure. The best combination of parameters was seed metering speed of 19.56r/min, suction negative pressure of 2.05kPa, and unloading positive pressure of 1.00kPa. Through bench test verification, the performance indexes were as follows: the average qualified index was 91.48%, the average missing index was 4.28%, and the average replay index was 4.24%. The results of seeding test showed that when the seed pressure was 0.8~1.0kPa, the working speed was 18~20r/min and the seed height was no more than 200mm, the coefficient of variation of grain spacing was not more than 13.2%, and the working performance was better. The research result can provide a reference for the design of vegetable narrow row close planting precision seeder.