A gas chromatography-tandem mass spectrometric(GC-MS/MS) method was established for the simultaneous determination of the contents of thirteen organophosphate retardants in lithium ion battery electrolyte.Organophosphate retardants in lithium ion battery electrolyte were ultrasonically extracted with ethyl acetate as extraction solvent.The extract was then condensed and filtered,followed by the analysis of GC-MS/MS.The external standard method was used to calibrate the concentrations of the retardants.The limits of detection(LODs) varied from 0.3 μg/kg to 30 μg/kg at a ratio of signal to noise(S/N) of 3,and the limits of quantification(LOQs) ranged from 1 μg/kg to 100 μg/kg at a ratio of signal to noise(S/N) of 10.The spiked average recoveries ranged from 80.4% to 94.6% with relative standard deviations(RSDs) of 3.8%-10%.The proposed method was simple,rapid,accurate and sensitive,and could meet the demands for routine analysis of organophosphate retardants in lithium ion battery electrolyte.