Abstract: In order to reduce the power consumption of sowing, improve the sowing quality and meet the agronomic requirements of precision seedling raising and sowing of hybrid rice, in this paper, the air suction double-layer cylinder seedling raising and sowing line was optimized and improved, and an independent air suction double-layer cylinder seedling raising and sowing device was designed. The working principle of the seeding device, the structure of key components and parameter design were described. The relationship between seeding quality and rotating speed of seed metering device and suction hole negative pressure was determined by force analysis of seeds in the process of seeding. The central composite test was carried out with qualified rate and repetition rate as experimental indexes, using vibration frequency, rotaing speed of seed metering device and suction hole negative pressure parameters as test factors. The results showed that the average qualified rate was 93.21% and the average repeat seeding rate was 3.97% when the vibration frequency was 51.8 Hz,  the rotating speed of seed metering device  was 8 r/min and suction hole negative pressure  parameter 3.4 kPa. The seed sowing device could satisfy the requirements of hybrid rice seedling and sowing.

Key words: double-layer cylinder, raising and sowing seedlings, seed sowing device, central composite face-centered design