The distribution and source of polycyclic aromatic hydrocarbons(PAHs) in multi-phase media(water phase,surficial sediments,surface coatings and suspended particulates) in the Nanhu Lake were investigated.The results show that 12 kinds of PAHs among the 13 kinds of PAHs were measured in surficial sediments,11 kinds were investigated in water phase and surface coatings,and only 7 kinds were investigated in suspended particulates.The accumulation capacity of surface coatings was similar to that of suspended particulates,and was much better than that of surficial sediments.This was due to the differences in the content of total organic carbon(TOC) among the surface coatings,suspended particulates and surficial sediments and the TOC content of surface coatings and suspended particulates was more than that of surficial sediments.According to the Pen/Anth and aromatic rings distributions of PAHs in the surficial sediments,the dominated source of PAHs in the Nanhu Lake was the combustion of fossil fuel.