Panax notoginseng is mainly grown in Yunnan Province. The planting area of Panax notoginseng has reached 672 km2 until December 2017. The row spacing and plant spacing of the seedlings of Panax notoginseng are only 50mm. In order to achieve high-density precision seeding of Panax notoginseng, an air-suction ultra-narrow-row device was designed for precise seed metering. Based on mechanical-pneumatic seed filling technology, the seed metering wheel had water drop-shaped holes on both sides. The seed metering device was compact. Compared with the air-suction cylinder seed metering device, the air chamber was smaller, which had lower requirements for air volume and wind pressure stability. The Wenshan Panax notoginseng seeds were chosen for seeding object. The simulation test of mechanical filling performance was based on the discrete element method, and the machining angle of water drop-shaped hole was taken as the single experimental factor. And the optimum of processing angle was obtained as 50°. Based on the three-factor quadratic orthogonal rotating combination test method, the influences of rotation speed of seed metering wheel, negative pressure of sucking hole and height of seed layer on seeding performance were explored. The experimental results showed that the affecting order of the qualified index was negative pressure of sucking hole, rotation speed of seed metering wheel and height of seed layer. Based on the results of examination, it was found that the fitting of the equations was good, the best parameter combination was pricking height of seed layer of 50mm, rotation speed of seed metering wheel of 34~48r/min and negative pressure of sucking hole of 560~660Pa, and under the optimal condition, the qualified index was greater than 93.0%, the missing index was less than 3.5%, the multiple index was less than 3.5% and variation coefficient of each row displacement consistency was less than 3.0%. The air-suction ultra-narrow-row device for precise seed metering met the standard and requirements by comparing the results with the national standard and Panax notoginseng planting requirements. The approach of research was suitable for the exploitation of Panax notoginseng seed-metering device.