The spiral seed-metering device is patent (patent No.ZL***6 2 ******0.8),which meets the need of precision seeding ,achieves adjustable quantity of seed, increases sowing uniformity .It is used widely to raise seedling of hybrid ,inbred ,super rice .The machine is domestic leading in the field of raising rice seedling industrialization on trays automatically，which is key technology of transplanting seedling industry. The machine will enhance the competitiveness of domestically produced precision sowing equipment, improve agriculture mechanization level, adjust agricultural structure of industry in China.