To determine the characteristics of soil selenium and its bioavailability，2735 topsoil samples and 141 groups of crop samples and their corresponding root soil samples were collected from the southern part of Fengjie，Chongqing.The contents of selenium in crops，selenium contents and other physicochemical indexes in soil samples were analyzed.The results showed that the surface soil selenium content in southern Fengjie ranged from 0.05 to 17.01 mg/kg，with an average of 0.45 mg/kg，and the total proportion of selenium-sufficient and selenium-rich soil was 97.02%.The Se contents in soils developed from carbonaceous shale and Permian Wujiaping formation were relatively high，averaging at 4.70 and 5.33 mg/kg，respectively.Among different soil types，the selenium content in yellow soil was relatively high，varying from 0.07 to 5.24 mg/kg，with an average of 0.60 mg/kg.Among different land use types，the highest selenium content of forest land was 15.4 mg/kg，with an average of 1.07 mg/kg，while the lowest content in paddy field was 0.10-0.98 mg/kg，with an average of 0.20 mg/kg.The results of Pearson correlation analysis showed that the soil selenium content was positively correlated with organic matter content and soil leaching intensity，and negatively correlated with pH.The ability of different crops to enrich selenium element ranked as rice>corn>radish.The correlation analysis and statistical results showed that soil parent material，land use type，soil organic matter，pH and iron aluminum oxide were the main factors affecting soil selenium content in the study area，and soil selenium content was the key factor affecting crop seed selenium content.It is recommended to plant corn and rice to build a special selenium-rich crop planting system and promote the development of local selenium-rich crop industry.