The Yangchuling large一sized porphyry tungsten-molybdenum orefield in the copper-sulfur-iron metallogenic belt of middle and lower reaches of the Yangtze River is genetically and spatially related to the granitic rock body in this orefield, This intrusive body，lying at the connection between the Jiuling upwarping zone of northern Jiangxi and the Lower Yangtze downwarping zone; is a complex rock body formed at the same stage by repeated activities of consanguineous magma and seems to be the product of 3rd stage of early Yanshanian(γ5^2-3).The rocks are intermediate-acid-acid and belong to 4th-5th family of 2nd class in Zavaritskii's classification. Researches show that the principal rock一forming mineral biotite in the ore-forming rock body of the orefield belongs to typical biotite of ferromagnesian series whose Mg-coefficient is close to Fe-coefficient, and is characterized by low F, Cl, Li and high Ti as compared with biotite in the Xihuashan rock body; plagioclase is of transitional-ordered texture whose deg- ree of order is 0.55-O.9,and has well-developed girdle band structure with An being 35-42; the degree of order(δ)of potash feldspar varies in the range of 0.19-0.5, belonging to transitional texture, and Or content is 50-80%。 Studies on typomorphic characteri stics of ore-forming mine rals indicate that the ore-forming rock body in the orefield was formed in a hypabyssal-supergene environment with the material sources characterized by anatexis, and this conclusion is supported by stable isotope and REE data of the ore-forming rock body in the orefield, In genetic type, this rock nody corresponds basically to the synte tic type granite proposed by professor Xu Keqin.