Spatial distribution, composition and possible source of 10 parent polycyclic aromatic hydrocarbons (PAHs) in littoral surface sediments from the Yellow Sea were investigated. The total PAHs concentrations varied from 12.4 to 8294.0 mu g/kg dry weights, and the sites with the highest levels were all located in Dalian Bay. At most sampling sites, PAH components with moderate and high molecular weights were dominant, while percentage of low molecular weight species was higher at a few sites close to several harbor cities. The specific ratios of paired PAH isomeric compounds for source apportionment suggested that various pyrolytic procedures were the major origin in the Yellow Sea, whereas petrogenic cause only occurred at a small number of the monitoring sites. The averaged effect rang low (ERL) quotient for the studied PAH components was generally below the threshold value of 1.0 in most sea areas, indicated that the potential ecological risks of PAHs contamination in surface sediments were normally not high in the Yellow Sea, however, the situation in Dalian Bay should be cautioned due to the high mean ERL quotient.