In this paper, the regional geological background and main geological structure pattern of Mianhuakeng uranium deposit were discussed at first. Then the hydrochemical feature of water gushing from geothermal boreholes in the deep part of the deposit, surface spring and surface water near the ore bearing belt was studied. The geological and geochemical forming process and genesis of geothermal water was summarized at final. It was pointed out that there are compound parts of multi-directional structures and a large amount of geothermal water in the deep part of Mianhuakeng deposit, The fault structure is conducive to the enrichment of hot water and provides deep groundwater recharge channel, which belongs to medium and low temperature convective geothermal system. The geothermal water supply source is atmospheric precipitation, which is controlled by the Mianhuakeng fault zone. The circulation is deep, and the energy exchange with the granite heat source layer is sufficient. The geothermal water has the characteristics of stable water temperature, large water volume and pressure.