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Considering that the existing seedling seeder for rice paddy field adopts manual push and pull, and has large differences in sowing performance, a precision seeder which was suitable for seeding in southern rice paddy fields was designed so as to reduce the intensity of labor and to improve the sowing qualified rate, uniformity and stability. A control system of the walking seeder was developed, which used STC12C5608AD singlechip microcomputer as the core control unit, PWM (Pulse width modulation) as control output of motor speed. The whole system has realized speed feedback with pure P proportional closed control algorithm, so that sowing performance of the seeder was stable and sowing qualified rate was about 5% higher than manual push and pull. Based on further analysis of sowing mechanism of spiral grooved wheel device, as well as control system of the walking seeder, the orthogonal tests were conducted to further investigate the effects of these parameters on sowing performance: depth groove (h),lead angle (α) of spiral grooved wheel and seeder speed (v). The results showed that the best operational parameter combination was that h of 3mm, α of 81.73°, v of 0.35m/s. Sowing performance tests based on the best parameter combination were done. After the control system was installed, the sowing qualified rate of hybrid rice (2～6 grains per grid) was improved from 87.14% to 93.21%, and the inbred rice (3～8 grains per grid) was 92.14%. Meanwhile, the empty rate of inbred rice was 0%, and the breakage rate was less than 0.20%. The control system has achieved automatic control of sowing process for seedling precision seeder, and the sowing performance can greatly meet the agronomic requirements of precision seedling in rice paddy field for hybrid rice and inbred rice. This study lays research foundation of precision seeding technology for rice paddy field seedling.