Good controlling effect to monocotyledon and dicotyledon weeds were achieved by spraying 47% atrazine,acetochlor and nicosulfuron SC after seedling in corn field.The controlling effect of weed quantity was 87.51% to 93.58% in 45 days after spraying,while the controlling effect of weed fresh weight was 87.29%～92.04%.Controlling effect was improved steadily as more chemical applied.All treatment had not bad influence to corn growing and development and the yield of all treatment was almost the same as artificial weeding.