Objectives：The Groundwater in the Tamusu uranium deposit possess the characteristics of rare high salinity in sandstonetype uranium ore deposit. In addition, it is found that the genesis of uranium mineralization is related to water—rock interaction. The main objective of this study is discuss the relationship between uranium mineralization and water—rock interaction.Methods: The groundwater characteristics (including salinity, type, and chemical composition) of the uranium mineralization layer in the Tamushu area were analyzed and the comparative analysis of different rocks (including granite in provenance area, normal sandstone, mineralized sandstone and uranium ore) and composition variation of plagioclase in the above were conducted. The formation and precipitation process in the rocks were studied, and the connection between uranium mineralization and water—rock interactions was established. Results: In a relatively closed environment，Na+ in high salinity (average salinity，354 g/L) and NaCl type groundwater in the Tamusu uranium deposit replace the Ca2+ in the plagioclases, transforming the plagioclase from the oligoclase (An≈13) to the albite (An≈1), and the substitued Ca2+ (with CaO， about 45% of the total mass) and the Mg2+，HCO-3，CO2-3 in groundwater formed carbonate cements such as dolomite. In the process，decarburization occurred, which promoted uranyl carbonate complex (such as \[UO2(CO3)3\]4-,\[UO2(CO3)2\]2- etc.) and MgCO3 ?Na2UO2（CO3）2 complex salt in groundwater segregation occurs and uranium precipitates. Due to diffusion,the uranium in the water trend to migrate to the relatively strong water—rock interaction region, which promotes the concentration and enrichment of uranium at specific geologic horizons. At the same time, plagioclase formed secondary cracks and pores on the cleavage and surface due to the water—rock interaction ( dissolution, etc.), providing space for uranium precipitation. After diagenesis, acidic surface water containing SO2- 4 and so on is infiltrated through the interlayer, dissolving carbonate cements in sandstones and forming caves, which provides precipitation space for the later migration of uranium, and forms the further superposition and enrichment of uranium. Conclusions: Two stages of water—rock interaction have been found in the Tamusu uranium deposit. The enrichment of uranium in specific geologic horizon occurs at the first stage, and the cracks and holes formed at the surface of plagioclase by the water—rock interaction (dissolution and corrosion，etc.) become the space for uranium precipitation. The second stage of water—rock interaction takes place after diagenesis, the interlayer infiltration of the acidic surface water containing sulfate solution dissolves the carbonate cement in sandstone to form holes, which provides space for further migration of uranium and further superposition and enrichment.