Abstract: Welsh onion sowed in spring was studied from 2009 to 2013.The results showed that this welsh onion should be sowed in greenhouse in early spring.The earlier it planted in field,the more nutrient accumulated in plant.And the single plant weight, pseudo stem length and yield increased higher.The proper density was 17000-15500 plants per 667m2.The better way for seed reproduction was that sowed in greenhouse from the middle of September to the middle of November,planted in next spring,and bolting rate and seed yield were optimal.