Abstract: In order to investigate the polycyclic aromatic hydrocarbons (PAHs) contamination of the surficial sediment in the south Coastal Mud Area off Zhejiang-Fujian(CMAZF), the content of polycyclic aromatic hydrocarbons in the surficial sediments were analyzed, and the distribution, sources and ecological threats of polycyclic aromatic hydrocarbons were also discussed. The results showed that the total PAHs concentrations of the surficial sediment in the south CMAZF ranged from 12.95×10^-9 to 156.05×10^-9. The results of isomeric ratio method and SPSS analysis indicated that PAHs in the study area mainly come from the combustion of coal and oil, and partly from oil source. The assessment results concerning with ecological risk evaluation of PAHs revealed that, to some extent, there might exist ecological risk in the surficial sediment of south CMAZF, and more attention should be paid to protect the marine environment.