The concentrations of petroleum hydrocarbon in 127 marine organisms trawled from Liaodong Bay in August, 2013, their distributioncharacteristics and the variation were studied to evaluate petroleum pollution. The results show that petroleum hydrocarbon concentrations in organisms were2.76~41.81 mg·kg-1 with an average of 12.19 mg·kg-1, and the content in organisms are in the following order: mollusks gastropoda> crab> molluskscephalopoda> shrimp> fish, and internal organs tissues was higher than muscle tiss...