The interlayered-oxidation zone sandstone type uranium deposits correspond spatially to the subzones of the interlayered-oxidation zone. The phases of ferrum are sensitive indicators of the geochemical environment changes. The FeFe2O3/Total Fe, Fe(FeCo3+FeS2)/Total Fe, FeFe2o3/Fe(Feco3+Fes2)Fe ratios are important parameters of the changes of the geochemical environment. Using the phases of ferrum and the parameters above to divide the subzones of interstratified-oxidation zone has both theoretical and practical significance in prospecting for u-ranium deposits of this type. The enrichment of minerals such as siderite and pyrite, which are sensitive to geochemical environment, in the transitional zone indicates that the geochemical environment is neutral-acidic and reductive and is propitious to the precipitation of uranium.