An　effective　high　performance　liquid　chromatographic　method　has　been　developed　for　the　determination　of　dye　methylene　blue(　M　B)　and　its　metabolites　azure　A　(　AZA),　azure　B　(　AZB),　azure　C　(　AZC)　in　aquatic　products,　and　applied　to　samples　of　incurred　samples,　which　had　been　dosed　with　methylene　blue.　Based　on　ion-pair　formation　with　p-toluenesulfonic　acid,　the　analyles　were　extracted　from　homogenised　tissue　using　acetonitrile,　partitioned　against　methylene　dichloride,　and　purified　with　a　mixed-mode　cation　exchange　solid　phase　extraction　cartridges.　The　linear　range　was　0.　005　-　0.　50　mg/kg　in　spiked　samples　and　the　correlation　coefficients　were　0.　9946　-　0.　9978.　The　average　recoveries　and　the　relative　standard　deviation　ranged　from　75.　9%　to　93.　2%　and　3.　3%　to　11.　9%,　respectively,　in　spiked　tissue　samples　at　concentration　levels　ranging　front　0.　005　to　0.　5　mg/kg　of　each　analytes.　The　limits　of　detection(　LOD)　of　AZA,　AZB,　AZC　and　MB　were　I.　27,　0.　98,　1.　48　and　1.　33　mu　g/kg,　respectively.　This　method　is　suitable　for　the　determination　of　methylene　blue　and　its　metabolites　residues　in　aquaetic　products　and　pharmacokinetics　study.