The utility model provides a Chinese yam seeder which comprises a ditching device, a seed metering device, a pesticide spraying device, a ridging device and a compacting device which are integrated, the seed metering device comprises a seed groove mechanism, the seed groove mechanism comprises a seed groove inner shell and a seed groove outer shell, and the seed groove inner shell is installed inthe seed groove outer shell in a push-pull mode; the utility model relates to a seed groove mechanism, a seed metering device and a seeder. Firstly, the seed groove inner shell is installed in the seed groove outer shell in a push-pull mode and can adapt to Chinese yam seeds of various lengths; inconvenience caused by the fact that a seed groove mechanism needs to be replaced for adapting to Chinese yam seeds with different lengths is avoided, meanwhile, mechanical operation of Chinese yam seeding is achieved, the rolling frequency of land is reduced, the seeding efficiency can be greatly improved, the labor cost is saved, and meanwhile a large amount of labor force is released.