In order to clarify the selenjum content of cultivated soil in Yunnan Province, 640 topsoil samples of farmlands in Yunnan were collected, and then its spatial distribution and influencing factors were studied. The results showed that the total Se content ranged from 0.05 to 7.12 mg/kg, with an average content of 0.51 mg/kg, reaching Se-rich level. Soil Se contents were different between different parent materials, which was highest in soils derived from basalt of basic crystalline salt type, with an average of 0.77 mg/kg. Soil type had a significant effect on Se content, Se content was significantly higher in brown soil, with an average of 1.24 mg/kg, while was the lowest in lime soil (0.21 mg/kg). Average Se content was higher in Qujing and Zhaotong than in other areas. Correlation analysis showed that Se content was not significantly correlated with soil pH, but significantly positively correlated with soil organic matter (r = 0.110, P<0.001), indicating that organic matter affects soil Se content.