In this study，a method was developed for simultaneous determination of 16 organophosphate esters（OPEs） in medical masks by ultra-high performance liquid chromatography－tandem mass spectrometry（UPLC-MS/MS）．In addition，the extraction and purification process for 16 OPEs was optimized．Specifically，three different extracting solvents including dichloromethane－,n,-hexane（1∶1），dichloromethane－acetonitrile（1∶1） and methanol，coupled with two purification processes，were compared. Meanwhile，the mask samples were ultrasonically extracted three times with methanol，then purified with ENVI－18 cartridges using 6 mL acetonitrile containing 25% dichloromethane as the eluent．The analytes were separated on a Acquity UPLC BEH C,18, column by gradient elution using 5 mmol/L ammonium acetate and methanol as the mobile phases，then analyzed in electrospray ionization positive（ESI+） mode under the multiple reaction monitoring（MRM） mode，and finally quantified by internal standard method．Results indicated that the limits of detection（LOD，,S/N, = 3） for 16 OPEs in mask were in the range of 0.004 60－1.03 ng/dm,2,，while the limits of quantitation（LOQ，,S/N, = 10） were 0.015 2－3.43 ng/dm,2,．The average recoveries for 16 OPEs in medical mask at three spiked levels of 5， 20 and 40 ng ranged from 68.8% to 140%，with relative standard deviations（RSD） of 0.70%－18%．These results indicated that the established method was suitable for the determination of OPEs in medical mask samples．The method was applied to the quantitation of 16 OPEs in forty-two medical mask samples．The total concentrations of 16 OPEs were in the range of 6.60－2 387 ng/dm,2,，with a median concentration of 34.2 ng/dm,2,．The detection frequencies for twelve OPEs were higher than 50%．Tri-phenyl phosphate（TPHP） and tri（1-chloro-2-propyl） phosphate（TCIPP） were the most abundant OPEs，with concentrations of 0.131－2 274 ng/dm,2, and 0.370－79.8 ng/dm,2,，respectively．Considering that the concentration of each analyte was relatively low，it is speculated that the OPEs in medical mask may be adsorbed from the air or transferred from plastic packaging during the manufacturing or packaging process．