Two methods including roasting-water leaching and direct acid leaching, were comparatively studied for the extraction of rubidium from the rubidium-bearing biotite. The leaching behaviors were investigated and optimized conditions were then obtained. For chlorination roasting-water leaching, the maximal rubidium extraction was obtained with a yield of 97.15% when at the mass ratio (CaCl2 versus minerals) of 0.4 and at temperature 900 degrees C after 10 min. For direct acid leaching, the optimized conditions for rubidium extraction were determined to be at sulfuric acid concentration of 5.52 mol/L, temperature of 80 degrees C, stirring speed of 250 rpm and liquid to solid ratio of 3, under the conditions of which, the extraction yield of 96.25% was obtained. Moreover, the mechanisms of reaction processes were further elucidated.