Abstract: The variations of pH, Eh and uranium concentration and other parameters with time during the process of uranium ore acidification and bacterial aeration were studied, and the relationship between the uranium ore leaching rate and the sulfur amount was explored. The results show that in the acidification stage, the pH and uranium concentration increase while the Eh decreases with the increase of acidification time in the same series of the acidification system. With the increase of acidification series, the change amounts of pH, Eh and uranium concentration in the acidification system decrease with the increase of acidification time. In the bacterial leaching stage, in the same series of the leaching system, the pH, Eh and uranium concentration increase with the leaching time, and the growth rates of the leaching system pH- and uranium concentration decrease with the increase of leaching series, while the growth rate of Eh increases. The pH of the leaching system decreases while the Eh and uranium concentration increase with the sulfur amount. The uranium ore leaching rate is positively related to the content of sulfur amount, and the uranium ore leaching rate reaches 95.45% in the leaching system with sulfur at 5 g/L.