Weathering affected to the changes of composition spilled oil resulting from Hebei Spilit accident (December 7, 2007, at South Korea) has been evaluated. More than 50 samples were collected from April to October 2008, along the Taean sound in Korea, located in 8 km away from accident spot. We examined relative abundance of the oil-related hydrocarbons naphthalenes, phenanthrenes, fluorenes, benzothiophenes, dibenzithiolhenes and isoprenoids potentials of biodegradation indicators from intertidal sediment. We found that biodegradation dominantly affected to short-term weathering in these area. The changes of relative abundance in dependent on alkylated number to parent PAHs, isomer selectivity and types of sediment, from surface to subside, has been investigated during 6 months. The microbial biodegradation indicators including selective depletion of naphthalenes and dibenzothiophenes evidently showed effective and selective occurrence of biodegradation. Other indicators more advanced biodegradation process including selective depletion of methylphenanthrenes and dimethylnaphthalenes were not showed significant alteration.