Abstract: In order to reveal the influence of human activities on the pollution of PAHs in the Songhuaba Reservoir in Kunming City, Yunnan Province, the vertical distribution and sources of PAHs in the two sedimentary core samples collected from the reservoir were studied. Core 1 was collected from the densely populated catchment area, while the catchment of Core 2 was collected from mountain watershed. The results show that the contents of ∑₁₆PAHs in Cores 1 and 2 ranged from 155.9 to 471.3 ng/g, and from 100.7 to 316.3 ng/g, respectively. The pollution level of Core 1 was higher than that of Core 2, which might be related to the higher anthropogenic emissions in the former area. The contents of ∑₁₆PAHs increased from the bottom to the top in Core 1 while it exhibited a decreasing trend from bottom up in Core 2. For the composition of PAHs, 2-ring Nap and 3-ring Phe accounted for more than 50% of ∑₁₆PAHs, and 4-6-ring PAHs with high carcinogenicity also had a large proportion. The results of both molecular ratio method and positive definite matrix factorization (positive matrix factorization, PMF) indicated that the main sources of PAHs were biomass fuel combustion (38.8%), petroleum (34.7%), coal burning (13.4%), and fossil fuel combustion (13.1%) for Core 1 and petroleum (44.4%), biomass fuel combustion (26.2%), coal burning (15.3%), and fossil fuel burning (14.1%) for Core 2, reflecting the differential patterns and intensities of human activities in those catchment areas.