Abstract: Undisturbed sediment cores can provide a record of changing environmental conditions and pollution levels. Polycyclic aromatic hydrocarbons (PAHs) in sediment cores can serve as indicators of the historical pollution processes due to their persistence and distinct source characteristics. In this study, changes in polycyclic aromatic hydrocarbons (PAHs) were studied in four sediment cores from the Fushui Reservoir, the largest reservoir in southeastern Hubei Province, and changes with depth interpreted with respect to their changing sources and environmental processing. The results showed that the total concentrations of 16 PAHs (Σ₁₆PAHs) ranged from 69.4 to 457 ng·g^-1, with medium- and high-molecular-weight PAHs being dominant. The highest concentrations of Σ₁₆PAHs in the sediment core were observed at the river inlet to the reservoir, which may be caused by the intensive anthropogenic activities in this area. Temporally, the concentrations of Σ₁₆PAHs continuously increased since the 1950s, peaked after the 1980s, and declined after 2010, which corresponded to the progress of socioeconomic development and the implementation of environmental governance measures. Source analysis revealed that PAHs in the Fushui Reservoir primarily originated from petroleum sources, petroleum combustion, coal/biomass combustion, and traffic emissions, which may be transported into the reservoir via catchment surface runoff and atmospheric deposition. Ecological risk assessment indicated that the PAHs in the sediment cores from the Fushui Reservoir posed low to moderate risks, with a declining trend in recent years. The findings of this study can provide a scientific basis and theoretical support for pollution prevention and integrated management of the Fushui Reservoir and its surrounding water environment.