The molybdenum content systematically analysed in ninteen species of plant which grow in trie Yangchulin Mo-rich geochmical rigion indicates that these species can be divided into three typs, i. e. high, medium and low limited type, The Mocontent of different tissue parts of high limited plants decreases in the following order:root, leaf, bark, old twig, young twig, and the sensitivity for indicating Mo mineralization is: twig>leaf>root. According to the relation with the avialable Mo in soil, the high limited plants is likely to be divided into A, B, C subtypes. Among A subtype plants, the Lespedeza buergeri is an ideal bio-geochemical explorating indicator for Mo mineralization in the region.