Abstract: Abstract: In China, the cultivation area of the facilities agriculture has reached 3.5 million hectares, and the industrialized farming will continue to develop during the period of the 12th "Five-Year Plan". The demand for intelligent equipment of facilities agriculture has become increasingly urgent with the rapid development of the ageing of population and the lacking of labor in rural areas of China. As for the air-suction seeders, there were many researches on positive pressure methods for dredging and ejecting seed head, but few reports about the research on the technology to prevent the seeding head blockage. The needle-type tray seeder consisted of seeding head, seeding pole, conveying cylinders, seeds plate, pneumatic vibrator, guide pipe, conveyor belt and so on. The seeds plate and pneumatic vibrator provide exciting force to boil the seeds to make the seeds being absorbed easily. Operations of absorbing the boiling seeds from the seeds plate and transporting the seeds to the guide pipe were implemented by the seeding head, seeding pole, conveying cylinders and guide pipe. In order to solve the problem that the suction nozzle of needle-type tray seeder was easily blocked to affect the quality of sowing, a kind of mechanical self-cleaning seeding head was designed based on air suction-blowing seeding principle. The structure of mechanical self-cleaning seeding head consists of a nozzle tip, fixed base, cleaning piston, thimble and reset spring and other parts. The suction nozzle was dredged by cleaning piston, and the seeding operation was performed by the thimble. The mechanical models that seeds were drawn at negative pressure and ejected mechanically at positive pressure were developed. The analysis results showed that the suction airflow rate was directly proportional to the inside diameter of the suction nozzle and inversely proportional to the height of suction position. The pressure of ejecting seed depended on the compression force of the reset spring, the gravity and adsorption force of seed. While the height of suction position was fixed, the negative pressure for sucking seed was negatively related to the inside diameter of the suction nozzle. While the inside diameter of the suction nozzle was constant, the negative pressure for sucking seed was positive correlated with the height of suction position. The experimental results showed that while the speed of seeding is 40 rows per minute, pickup vacuum is 35 kPa, shooting-seed pressure is 50 kPa, the single seed rate, cavity rate and repeat seeding rate were 95.31 %, 1.56 % and 3.13 % respectively, which increased by 7.81%, 6.25% and 1.56% respectively than traditional suction nozzle. The quality of sowing and effects of anti-blocking were improved significantly, so the self-cleaning seeding head can replace the traditional needle-type suction nozzle. The research can provide a reference for further improving quality and optimizing the parameter for self-cleaning seeding head.