Gold and silver orebqdies in the Changkeng ore district mainly in siliceous rocks and limestone immediately under the uncomformity between the Lower Carboniferous limestone and the Upper Triassic carbonaceous shale. Gold and silver orebodies are separated from each other. Gold mineralization, which is enriched in Hg. As and Sb occurs as disseminations in siliceous rocks; while silver mineralization, which is enriched in Cu, Pb and Zn, occurs as veins in siliceous rocks and limestone. Lead isotopic composition of gold mineralization varies in the same range as those of Cambrian to Carboniferous strata and the gold - hosted siliceous rocks. Lead isotopic composition of silver ore differs from that of the gold ore. Hydrogen, oxygen and carbon isotopic compositions of gold ore -forming fluids and silver ore -forming fluids differ from each other. The Rb - Sr isochron age of silver mineralization is 70. 4 Ma. It is concluded that the gold deposit resulted from hydrothermal - sedimentary processes, while the silver deposit from late Yanshanian reworking processes.