By taking the common aquatic products on the market as material, an analytical method for the determination of 8 polycyclic aromatic hydrocarbons (PAHs) in aquatic products by liquid chromatography-mass spectrometry was established. The sample was extracted by ultrasonic assisted acetonitrile, and the extract was cleaned up with C18 and Florisil chromatographic bi-column, detected with LC-MS/MS for PAHs. The results showed that the 8 PAHs could be separated efficiently. The detection limits of this method were 0.006~0.105μg/kg. The relative standard deviations were ranging from 0.3%~4.0% (n=4), and the recovery rates were from 86%~110%. The method proposed by this paper possesses higher producibility and selectivity, and has promising applications in determining the PAHs in aquatic products.