Abstract: In order to explore the characteristics of heavy metal pollution in the soil of closed mining areas，analyze the sources of pollution，and distinguish the contribution rate of geological causes and hu⁃ man industrial and mining activities，the soil of a closed mining area in Tongling City，Anhui Province was taken as the research object，and the principal component analysis（PCA）was used to identify and ana⁃ lyze the sources of heavy metals. The results show that the cumulative variance interpretation rate of the three principal components extracted is 70.935%，and the factor combination of principal component 1 （40.863%）is Cu，Pb，Cd and Sb，which is highly consistent with the geological structure and is interpret⁃ ed as the source of geological genesis. The factor combination of principal component 2（15.565%）was As and Hg，which was related to the pollution of anti-corrosion enterprises in the area. The factor combination of principal component 3（14.417%）is Cu，Cd，Hg and Sb，which is related to the non-standard storage pollution of battery enterprises，copper products enterprises and early tailings in the area. The high geo⁃ chemical background has a high contribution rate in the accumulation of heavy metal pollution in the soil of the mining area，and it is recommended to pay full attention to the site control and remediation in the later stage.

Key words: heavy metal, principal component analysis, source analysis, geological background source