The aryl hydrocarbon hydroxylase(AHH) activity of carp liver microsome induced by five polyaromatic hydrocarbon (PAH) compounds was examined Five tested PAH named as phenanthrene; 9,10 phenananthrenquinone, pyrene, benzo[a]pyrene, 1 hydroxypyrene induced AHH activity to different extent There existed a good dose effect correlation between the AHH induction and aromatic hydrocarbons concentration The AHH activity of fish liver microsome can be used as a biomarker to evaluate the aromatic hydrocarbon contamination in waters The intense of AHH activity induced by five aromatic hydrocarbons which was related to the toxicity chemicals was as following: 1 hydroxypyrene benzo[a]pyrene; 9,10 phenananthrenquinone pyrene phenanthrene