Abstract: The present disclosure provides a method for numerical simulation of reactive transport during CO2+O2 in-situ leaching of uranium at a sandstone-type uranium deposit. Unlike the traditional method for numerical simulation of solute transport during in-situ leaching of uranium with consideration of only convection and diffusion, the method permits establishment of a multi-field coupled reactive solute transport model to simulate the dynamic leaching process of a sandstone-type uranium deposit in Northern China. The method provided in the present disclosure includes: creating a thermodynamic database suitable for CO2+O2 leaching of a sandstone-type uranium deposit in Northern China, and with consideration of the dynamic reaction process of uranium dissolution under combined action of oxygen O2 (aq) and bicarbonate HCO3?, performing numerical simulation of reactive transport during CO2+O2 in-situ leaching of uranium using a TOUGHREACT simulation technology framework.