▎ 摘　　要

NOVELTY - The preparation method of biomass-based hierarchical porous carbon, involves: either pre-carbonizing the biomass to obtain pre-carbonized porous carbon and mixing the pre-carbonized porous carbon with activating agent for carbonization treatment, where the porous carbon comprises microporous, mesoporous and macroporous; or mixing a biomass and template agent for carbonization treatment to obtain carbonized product, where the template agent is magnesium salt or magnesium oxide, using acid leaching method to remove the template agent in the carbonized product; or mixing the biomass, water and the oxidized graphene solution and drying to obtain the biomass powder precursor, performing the first carbonization treatment to the biomass powder precursor to obtain the first biomass-based porous carbon, mixing the first biomass-based porous carbon with potassium hydroxide carbonization treatment. USE - Preparation method of biomass-based hierarchical porous carbon used in chemical production, medical carrier, environment protection, electrode material, soil improvement and as catalyst or catalyst carrier to participate in catalytic reaction, used as electrode material in electrochemical device and purifying water purifying agent. ADVANTAGE - The preparation method is simple and easy. The prepared biomass-based graded porous carbon has large specific surface area and multi-stage hole composite structure.