An effective method for decolorization of the polysaccharides from Lethariella spp. was studied. Decolorization rate was used as an indicator in the experiment, single factor text and orthogonal experiment was used to get the optimal conditions, the single factor experiment was carried out with temperature at 35°C, 45°C, 55°C, 65°C, and 75°C, the activated carbon added at 0.5%, 1%, 1.5%, 2%, and 2.5%, and time at 10, 15, 20, 25, and 30min, respectively. The optimal conditions of Lethariella spp. clarification using activated carbon were carried out to get the optimal conditions (the temperature at 55°C, the activated carbon added at 1%, and time was 25 min, and the decolorization rate could reach 57.56 %).