Phosphoric acid activated carbon with husk as raw material, H3PO4 as activator to prepare can be used for citric acid, monosodium glutamate, lactic acid, xylose and other products production decolorization of activated carbon. The effects of immersion time, liquid-solid ratio, H3PO4 concentration, reaction activation time and temperature on product yield, methylene blue decolorization and caramel decolorization were studied. The yield, methylene blue decolorization and caramel decolorization of activated carbon prepared at room temperature (25 ℃) for 3 d, liquid-solid mass ratio of 2.5 ∶ 1, H3PO4 mass fraction of 65%, activation temperature and time of 550 ℃ and 1 h, respectively, were 46% 1, 3 mL and 100, respectively. Activated carbon is widely used in chemical industry, medicine, food, light industry, environmental protection, water treatment and other fields because of its developed pores and huge specific surface area.