Abstract: To scientifically investigate the degree and sources of heavy metal pollution in the soil of a steel plant contaminated site, this study selected a steel plant in Chongqing as a case study. A systematic sampling design was employed to collect 356 surface (0~0.30 m) soil samples within the plant area. The concentrations of eight heavy metals (Hg, Cu, Cd, Pb, Zn, As, Ni, Cr) in the samples were analyzed. The pollution status, distribution characteristics, and sources of heavy metals in the steel plant's contaminated soil were evaluated and analyzed using the Single Factor Pollution Index method, the Modified Nemerow Comprehensive Pollution Index method, correlation analysis, principal component analysis (PCA), and the Positive Matrix Factorization (PMF) model, combined with Kriging spatial interpolation. The results showed that the average concentrations of the eight heavy metals in the study area were all higher than the background values of Chongqing's soil environment, with Hg and Cu being particularly prominent, having standard exceedance rates of 71.91% and 64.61%, respectively. Spatial distribution indicated that soil heavy metal concentrations showed a trend of radiating outward from the plant area as the pollution center. The soil heavy metal pollution assessment indices revealed severe pollution of Hg and Cu, with the single heavy metal pollution degree ranked as Hg > Cu > Cd > Pb > Zn > As > Ni > Cr. The comprehensive pollution in the study area was serious, accounting for 86.52% of the area, with the southwest and central plots being more severely polluted. The high-pollution areas were mostly located in the plant area and its surrounding environment, indicating that the heavy metal contents in the soil were influenced by anthropogenic factors. Principal component analysis and the PMF model demonstrated that As, Cd, Zn, Pb, and Cr primarily originated from industrial and natural comprehensive sources, Cu and Ni were mainly from industrial sources, while the sources of Hg were relatively complex. The zoning for soil heavy metal pollution control indicated that the entire study area was under strict control. The heavy metal contents in the soil of the study area were generally higher than the background values, with Hg and Cu pollution being the most severe. The pollution was spreading outward from the plant area as the center, primarily originating from industrial activities. The subsequent prevention, control, and remediation processes should focus on the risk management of Hg and Cu.