Abstract: The distribution, sources and risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Dagu River estuary in Jiaozhou bay, China, have been investigated in the research. The results indicated that the total concentrations of 16 PAHs in surface sediments of the Dagu River estuary ranged from 21.93×10^-9 to 634.64×10^-9 with a mean value of 239.41×10^-9, which was of the moderate level of PAHs pollution and relatively low in comparison with other estuaries and bays around the world. The concentration of PAHs in the surface sediments from the Dagu River estuary in July was much higher than in October, and Fluorene, Fluoranthene, Pyrene had the highest mean values of 58.10×10^-9, 28.71×10^-9, 23.69×10^-9, but Acenaphthylene was with the lowest value of 0.65×10^-9. The PAHs in the study area were mainly originated from petroleum combustion. Besides, the PAH may be contaminated by petroleum as indicated by the selected ratios of PAHs and principal components analysis at different sites. The result of the ecological risk assessment shows little negative effect for most individual PAHs in surface sediments of the Dagu River estuary in Jiaozhou bay. And the risk assessment of PAHs for human was determined by the BEQ of Benzo (a) pyrene, which suggested that the toxicity of PAHs have little potential risk for people's health.