Abstract: A rapid analytical method for simultaneous determination of nicosulfuron,atrazine and fluroxypyr in corn and soil was established based on QuEChERS with ultraperformance liquid chromatography-mass spectrometry(UPLC-MS/MS).Residues were firstly extracted with acetonitrile(containing 2% formic acid),and then detected by UPLC-MS/MS with external standard method after being cleaned up with matrix solid-phase dispersion.The results showed that the established method was rapid,simple,high efficient and sensitive.A good linearity ranged from 0.01-1.0 mg/L was obtained and correlation coefficient was higher than 0.990 6.The average recoveries of the three herbicides in different matrices were in the range of 78.9%-117.7% at spiked levels 0.02-0.5 mg/kg,with intra-day relative standard deviations lower than 11.6% and inter-day relative standard deviations lower than 13.9%.The limits of quantification(LOQ)of three pesticides in corn and soil were lower than 7.1μg/kg.