In order to fully understand the air pollution characteristics and sources of pollutants in the site area of Jinsha Site Museum, PM2.5 and VOCs levels in the atmosphere inside and outside the Site Protection Hall were observed in the fall of 2019, and their respective chemical components were comprehensively analyzed. The results show that 1) the atmospheres inside and outside the Jinsha Site Museum’s Site Protection Hall were both severely polluted by PM2.5, with their average mass concentrations of 77.0 and 94.6 μg/m³, respectively; 2) the difference between day and night levels indoors was significantly larger than that outdoors due to the degree of human activity; 3) the concentrations of OM, NO-₃ and SO2-₄ were higher outdoors than indoors, while the concentrations of NH⁺₄ and typical crustal elements (K⁺,Mg²⁺ and Ca²⁺) were higher indoors than outdoors; 4) indoor and outdoor PM2.5 levels were respectively alkaline and acidic due to the influence of their chemical compositions; 5) crustal elements dominated, with their indoor and outdoor proportions reaching 82.8% and 84.4%, respectively; 6) according to the analysis of the enrichment factor, it was found that the elements of Cu (outdoor), Ag, Cd and Sb had reached a severe enrichment; 7) the indoor and outdoor concentrations of VOCs were almost the same, 81.2×10-9 and 81.3×10-9, respectively, alkanes, contributing the most, accounting for 44% and 46%, respectively; 8) the outdoor concentrations of VOCs, derived from artificial sources such as motor vehicles, industrial solvent coatings, fuel volatilization and biomass combustion, were significantly higher than indoor concentrations. These research results were of a great significance for a comprehensive understanding of the air quality in the site area of Jinsha Site Museum, the high-quality preservation of earthen site and the cultural relics therein, and the provision of a quality visiting environment.