Abstract: A method of HPLC and AFS in hyphenation for the determination of the species of 3 mercury compounds in aquatic products was proposed. Sample of aquatic product was extracted with a solution containing thiourea, KCl and HCl, and the extract was cleaned up on C18 SPE column, and separated on C18 chromatographic column, and then determined by atomic fluorescence speciation analyzer. Linear relationships between values of fluorescence intensity and mass concentration of Hg2+, CH3Hg and CH3CH2Hg were kept in the same range from 1.00 to 50.0 μg · L-1, with lower determination of limits (10S/N) of 0.03 mg·kg-1 for Hg2+ and CH3Hg, and 0.04 mg·kg-1 for CH3CH2Hg. The proposed method was applied to the analysis of aquatic products, giving values of recovery obtained by standard addition method in the range of 73.3%-87.4% and RSD′s (n=6) in the range of 3.6%-9.1%.