A liquid chromatography-tandem mass spectrometric(LC-MS/MS) method was developed for the determination of brilliant green,methylene blue and their metabolites in aquatic products.The samples were extracted with ammonium acetate buffer solution and acetonitrile,followed by extraction with dichloromethane,then purified on a PRS solid phase extraction column.The eluent was concentrated by nitrogen blowing,diluted to a certain volume and determined.The targets were separated on a CAPCELL PAK C18 column with 2 mmol/L aqueous ammonium acetate containing 01% formic acid,acetonitrile and methanol as mobile phases.The determination of the analytes was performed by LC-MS/MS in selected reaction monitoring(SRM) mode,and the external standard method was used for quantitation.There existed good linear relationships for the analytes in the range of 10-100.0 μg/L with their correlation coefficients(r2) larger than 0.999.The limits of detection(LOD,S/N≥3) and quantitation(LOQ,S/N≥10) were 1.0 μg/kg and 2.0 μg/kg,respectively.The average recoveries at three spiked levels of 1.0,5.0 and 10.0 μg/kg were in the range of 70.3%-92.1% with their relative standard deviations(RSDs,n=6) of 23%-13%.The method has high sensitivity and could be used in the effective detection on residues of brilliant green,methylene blue and their metabolites in aquatic products.