Polycyclic aromatic hydrocarbons (PAHs) in the dated sediments from the Shuanglong catchment in the southwest of China were measured to characterize source inputs. The PAHs concentrations in the priority controlling list of US EPA (∑PAHs) ranged within 102.47~563.24 ng g⁻¹, with an average value of 207.18 ng g⁻¹. The 2-3 rings PAHs were predominant, accounting for 73.77% of ∑PAH. According to the classification of pollution levels, ∑PAHs concentrations in the sediments are within the range of moderate pollution level. Both the total and individual PAH concentrations changed with the depth. The profile distribution of PAHs concentration in the sediments suggested that PAHs acted as an effective way to reconstruct the historical trends of socioeconomic changes in the study areas. Results of Ant/(Ant + Phe), Fla/(Fla + Pyr), and BaA/(BaA + Chry) show that petroleum and petrogenic matter are attributed to the potential pollution source in the Shuanglong catchment. The coal combustion and incomplete combustion of gasoline and fossil fuel are dominant. TOC contents had positive correlation with ∑PAHs (R2=0.72, P<0.001), 2-3 rings (R2=0.44, P<0.001), 4-ring (R2=0.78, P<0.001), and 5-6 rings (R2=0.62, P<0.001).