The analysis of PAHs in sediments of 12 sampling sites from Chongqing section of the Yangtze River shows that total PAHs concentration ranges from 0.64~3.98 μg/g in dry season and 0.85~4.63 μg/g in wet season,with the maximum content of phenanthrene accounting for 11%~27% of total PAHs. The 3~5 rings PAHs are dominant in sediment samples,while the content of PAHs with 2 and 6 benzene rings is small. Moreover,the compositions of PAHs are significantly different as they are taken from different sampling periods,releasing more 6-ring PAHs in rainy season. The combustion of fossil fuels and oil spillages of ships may be dominant sources in the study area and the degree of sediment contamination by PAHs is moderate in comparison with other internal and external sediments. However,fluorene and phenanthrene exceed the probable effect level (PEL),which might certain potential damage to the ecosystem in the studied area.