By a series of survey, results of field trails were as follows: Excellent weed control performance were achieved when applied at 3-4 leaf stage of corn with the dosage of 0.9～2.4g.ai/hm2.Average controlling percentage against barnyard grass was 41.6%～88.1% and that against all kinds of broadleaf weeds was 68.2%～94.0%.The total fresh weight of weeds was decreased by 81.0%～92.9%.The results showed that Sulcotrione-Atrazine 40% SC is a broad spectrum and persistent herbicide.It could raise the output of corn by 98%.