Investigating selenium(Se)content characteristics and enrichment mechanisms in the soil-rice system of the northern Hunan region can provide a scientific basis for the development and utilization of regional Se resources.Based on the determination of selenium content and related mineral nutrients in 25844 paired soil-rice samples from the Northern Hunan region，this study employed ordinary Kriging interpolation，redundancy analysis，variation partitioning analysis，and hierarchical partitioning analysis to explore Se content characteristics in the soil-rice system and reveal influencing factors of soil Se enrichment and rice Se accumulation mechanisms.The results showed that the average values of soil Se，rice grain Se，and the bioaccumulation factor(BCF)were 0.485 mg/kg，0.063 mg/kg，and 0.147，respectively.The soil Se enrichment rate was 60.69%，while the rice grain Se enrichment rate was 77.87%.The spatial distribution of rice grain Se aligned with soil Se，exhibiting a pattern of higher levels in the west and lower levels in the east.Significant differences(P<0.05)in soil Se，rice grain Se，and BCF were observed among soils derived from different parent materials.In non-enriched soil and non-enriched rice(NN)systems，soil organic matter(SOM)，Zn，and cation exchange capacity(CEC)were significant factors influencing Se content.In non-enriched soil but enriched rice(NR)systems，SOM，CEC，and pH played critical roles.For enriched soil but non-enriched rice(RN)systems，elevation，pH，and Zn were key influencing factors.In enriched soil and enriched rice(RR)systems，elevation，precipitation，and Zn significantly affected Se content.The northern Hunan region has high Se content in cultivated soils and abundant Se resources.Comprehensive analysis of soil properties and environmental factors is essential for rational development of soil Se resources and cultivation of selenium-enriched rice.