Abstract:CO2+O2 neutral leaching experiment was conducted in laboratory to study uranium leaching rate under different conditions using sandstone type uranium ore from Xinjiang as raw materials. Compound leaching agent was from ore-bearing groundwater and in-situ leaching tailings. It aims to study oxidation of Fe and S, and dissolution and precipitation of carbonate which may affect on in-situ leaching. The results show that there is no significant difference between leaching results of leaching agent prepared by groundwater and in-situ leaching tailings. Uranium content of ore is the most important factor, and leaching uranium concentration has a significant positive correlation with uranium content of ore. Static leaching result show that diffusion of uranium in system is not sufficient, namely, uranium concentration in bottom is significantly higher than that in upper, that may be the reason why leaching rate of uranium in static leaching is lower than that in stirring leaching. After leaching, FeO content of ore drops by 37%—62%, and S is also oxidized. When carbonate is nearly saturated or supersaturated, pH value of system should be controlled within 6.5 to avoid saturated precipitation of calcite and dolomite.