The suspending herbicide agent composed of 30% fluroxypyr,Nicosulfuron and atrazine was applied in corn field.Results of efficacy test showed that the effect of control the weed was 93.5～97.3% under 382.5～450g.ai/hm² applied at 3～6 leaf stage.The effect of controlling malignant weeds was satisfied.It is safety to corn,and corn yield was increased significantly than manual controlling of weeds.