A new and efficient low-temperature chlorination-roasting–acid-leaching uranium process was proposed to solve the problems of low leaching efficiency, since the leaching residue does not meet the discharge standard in the traditional nitric acid leaching-uranium tailings process, compared with conventional chlorination roasting. XRD, SEM, particle size analysis, and other analytical methods were used to characterize and analyze the phase transformation and structural changes in the roasting process of uranium-containing tailings. An investigation was conducted to elucidate the influence of roasting temperature, NaCl addition, and roasting time on the leaching efficiency of uranium. Compared with conventional chlorination roasting, microwave chlorination roasting can effectively destroy the gangue mineral structure of dissolved slag; the surface cracks of uranium tailings increase, and the particle size is smaller, so that the uranium element is fully exposed, thereby improving the leaching effect. Because microwave heating has the characteristics of selective heating and rapid heating, when the microwave-roasting power is 2000 W, the sample only needs 12 min to be heated to optimal roasting temperature, which is 8 min shorter than the conventional heating time, and the leaching rate of uranium is further improved. In the microwave roasting experiment, the roasting temperature is set to 250 °C, roasting time is 90 min, and addition amount of NaCl is 25 wt % of the tailings mass. Under the optimal roasting conditions, the leaching rate of uranium is 94.84%.