Abstract: A rapid method for determination of cyromazine residues in common bean(Phaseolus vulgaris) and soil was established based on ultraperformance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The sample was extracted with 5 mmol/L solution of ammonium acetate and acetonitrile V(acetate):V(acetonitrile)=1:4 and then purified by primary secondary amine(PSA).The cyromazine residues were analyzed by UPLC-MS/MS under multiple reaction monitoring mode and quantified with external standards.Average recoveries of cyromazine in common bean and soil at three levels(0.05,0.5 and 1 mg/kg) ranged from 80.1% to 95.2% with relative standard deviations from 1.9% to 9.1%.Limits of detection of cyromazine were 3.8-5.9 μg/kg,while limits of quantification were 50 μg/kg.The method is simple and suitable for the routine and confirmation analysis of cyromazine residue.