Abstract: A ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) method for the simultaneous determination of 4 benzoylurea pesticides (lufenuron, chlorbenzuron, chlorfluazuron and diflubenzuron) in citrus fruits was established. The procedure was based on QuEChERS cleanup and determination with UPLC-MS/MS. The results showed that the calibration curve was linear in the range of 0.01-0.2 mg/mL and correlation coefficient(r) higher than 0.994. The average recoveries of 4 pesticides were 92%-105% when the spiked levels were 0.01, 0.05 and 0.1 mg/kg, with relative standard deviations (RSD) between 0.4% and 3.3% (n=5). The limits of quantitation (LOQ) for 4 pesticides were 0.01 mg/kg. The method is accurate, sensitive, simple, suitable for the simultaneous determination of 4 pesticide residues in citrus fruits.