The problem of how to use geological results or data, especially from the eco-geochemical survey engineering, has been an issue attracting extensive attention since the 21^th Century. By studying the regional eco-geochemical survey and some petrogeochemical survey data of Se distribution in soil, the authors investigated and summarized relevant selenium-rich soil space distribution characteristics in Jiangsu Province, element geochemistry, material sources and genetic types, and some other problems. The main research results are as follows:1) The proportion of selenium-enriched soil is less than 3% in Jiangsu Province, and Se concentration in the selenium-enriched soil is generally 0.3-15.0 mg/kg. In addition,, there are restively higher element values of S, TOC (total organic carbon), Zn, Sb, Cd, Pb, As, Cr, Ni, Fe, etc., in the soil; 2) the above selenium-enriched soil can be divided into 6 genetic types,i.e., the original rock weathering residual type, coal gangue weathering migration type, local lacustrine sediments Se-rich type, coal flyash type, superposition type of some heavy metals pollution, and polymetallic mineralization associated type. Meanwhile, the utilization values of the original rock weathering residual type selenium-rich soil are the highest and it is mainly from acid soil environment in southern Jiangsu Province, and this type Se-rich soil is the main production area of Jiangsu's natural selenium-rich agricultural products; 3) the material sources present multi-origin compound attributes in the Se-rich soil, and they are manifested as three main material forms in the Se-rich soil, namely the congenital materials sources of natural origin, acquired materials sources of man-made origin, and compound materials sources of natural and man-made common origin; 4) there exist significant positive correlation between Se and S, TOC, etc., in the Se-rich soil formed by congenital materials sources of natural origin, and the values of some heavy metals such as Cd, Zn, Pb and As rarely exceed the standards of national farmland security utilization in this kind of Se-rich soil. Moreover, the category or thickness of this kind of Se-rich soil are not restricted by the cultivated layer, and the most thick soil of Se-rich areas can exceed 2 meters in depth.