Abstract: Objective:An effective method was developed for the simultaneous determination of 11 organophosphate esters in aquatic product,based on ultrasound-assisted extraction coupled with LC-MS/MS. Methods:Samples were extracted by ultrasonic,and then the target compounds were analyzed by LC-MS/MS under positive electrospray ionization,and quantified by the multiple reaction monitoring. The conditions,including extraction solvent,extraction volume,extraction time and moving phase,were studied. Result:Under the optimal experimental conditions,dichloromethane was used as the extraction solvent with extraction volume 10 mL,ultrasonic time was 10 min,and mobile phase was methanol containing 0.1% formic acid-water containing 0.1% formic acid. 11 kinds of organophosphate esters were successfully separated,the correlation coefficients were more than 0.998,the quantitation limits ranged from 0.020~5.71 μg·kg^-1,the recoveries were in the range of 91.2%~110.5% with the RSDs of 0.14%~6.6%. Conclusion:The method pretreatment was simple,rapid and effective,and could be applied in the determination of 11 kinds of organophosphate esters in aquatic product.