【Objective】Southeast Zhejiang is an important ecological barrier and an enrichment area of characteristic agricultural resources along the southeast coast of China, possessing rich selenium (Se) resources. A detailed understanding of the spatial heterogeneity of soil selenium and its controlling factors is fundamental for planning Se-enriched agriculture and managing land resources sustainably. However, systematic investigations on the spatial distribution patterns of soil selenium and its key driving factors in this region remain insufficient. 【Method】This study selected Wenzhou City, a representative area with complex geology and diverse land use within southeastern Zhejiang, as the research focus. The primary objectives were to: 1) characterize the spatial distribution of Se in surface soils; 2) evaluate the influences of various natural and anthropogenic factors on soil Se content; and 3) identify the dominant factors controlling its spatial variability. Following the technical specifications for 1:50,000 land quality geochemical surveys, a systematic sampling strategy was designed and implemented, collecting 25,753 topsoil samples (0–20 cm depth). Field investigations of geology and geomorphology, laboratory analyses of soil nutrients, heavy metals, and selenium content, as well as GIS-based spatial analysis, correlation analysis, and multiple regressions, were comprehensively integrated to systematically explore the spatial distribution patterns of soil Se and its primary controlling factors in Wenzhou.【Result】The results revealed that the average Se content in the topsoil soils of Wenzhou City was 0.32 mg·kg⁻¹, with a range of 0.03 to 2.54 mg·kg⁻¹.The coefficient of variation was 40%, indicating a moderate degree of variability. The Se-rich soil (selenium content ≥ 0.4 mg·kg⁻¹) accounted for 25.6% of the total area of the region.Also, the geostatistical analysis demonstrated a strong spatial autocorrelation for soil Se, with an effective range of approximately 13.35 km based on the best-fitted exponential semivariogram model (R2=0.994). In addition, the spatial distribution exhibited a clear regional pattern, characterized by significantly higher Se levels predominantly in the central part of the city, encompassing low mountainous and hilly areas like Ouhai and Ruian, compared to the eastern and western regions. Stratigraphic unit, soil parent material, geomorphic type, soil type, land use type, and soil texture all had significant effects on soil Se variation, among which parent material played the most dominant role. Soil Se content was significantly negatively correlated with soil pH, while showing significant positive correlations with organic matter, total nitrogen, and heavy metals. Multiple regression analysis indicated that soil type, parent material, pH, and arsenic content were the primary factors controlling soil Se spatial differentiation.【Conclusion】The spatial differentiation of surface soil Se in Wenzhou City is the result of the combined action of multiple factors such as geological background, soil physical and chemical properties, and human activities. These findings provide a scientific basis for regional land quality evaluation and the rational development and utilization of Se-rich characteristic agriculture.