Abstract: In Zaohuohao-Nalinggou area, based on the SEM (scanning electron microscope) test results of total rock and minerals for all 111 samples, XRD (X ray diffraction) and macro elements test for some samples, with the combination of knowledge of genetic mineralogy and prospecting mineralogy, the physical property, shape of clay mineral and uranium mineral, clay minerals component and pH of mineralized solution for mineralized rock and wall rock from the Lower Sub-Section of Zhiluo Formation have been analyzed.The results show that the paleo-climate variation and long-term depositional break existed in the upper Yan'an Formation have active significance for the uranium mineralization in this area, and the diagenesis and mineralization of different rock in syn-depositional stage are all favorable to uranium enrichment.In carbonate solution, reaction from U⁺⁶ to U⁺⁴ must occurs in strong reducing environment.Calcareous sandstone can be regarded as the migration pathway of mineralized solution for uranium mineralization.Mineralized sandstone, gray sandstone, green sandstone and celadon sandstone were all formed in different depositional environment.Redox transitional zone may be the most favorable place for uranium prospecting.