Abstract: With the rapid industrialization of China, industrial parks have become crucial engines for economic growth. However, they have also led to environmental issues such as soil heavy metal pollution. The long-term operation of an industrial park in western Jiangxi Province has raised concerns about its impact on surrounding farmland. To assess the influence of the industrial park on heavy metal contamination in adjacent agricultural soils and to support green, sustainable development and agricultural safety, 153 surface soil samples and 19 vertical soil profiles were collected from the surrounding area. The concentrations of trace elements (e.g., Cd) and major indicators (e.g., Fe) were determined using atomic fluorescence spectrometry (AFS), inductively coupled plasma-mass spectrometry/optical emission spectrometry (ICP-MS/OES), and X-ray fluorescence spectrometry (XRF). Pollution and risk characteristics were analyzed, and source apportionment was conducted using principal component analysis (PCA) and positive matrix factorization (PMF), with priority control factors identified. The results showed that, except for As and Pb, the average concentrations of Cd, Cu, Cr, Hg, Ni, and Zn in the surface soils were 1.01–3.55 times higher than the background values of Jiangxi Province. The Nemerow pollution index and potential ecological risk index indicated that Cd was the primary contaminant and ecological risk factor. Combined PCA and PMF analysis identified six sources of soil heavy metals: secondary enrichment in red soil (38.2%), parent rock weathering (17.8%), agricultural activities (15.6%), industrial park emissions (10.9%), upstream mining discharges (10.2%), and industrial coal combustion (7.3%). Analysis of the relationship between heavy metals, pollution sources, and potential ecological risks showed that emissions from the industrial park exhibited the highest comprehensive potential ecological risk index (RI), accounting for 41.3% of the total risk, with Cd contributing 97.4% of the RI from this source. In conclusion, Cd is the predominant pollutant in the surface soils of the study area, and industrial park emissions constitute the primary source of potential ecological risk, already impacting surrounding farmland. Measures must be implemented to prevent further exacerbation of this contamination.