The invention relates to a method for increasing the specific resistance of a biomass charcoal reduction agent for industrial silicon smelting and belongs to the technical field of nonferrous metal smelting. Biomass is smashed into particles with the granularity being 0.5-5 cm, and then a copper slag catalyst is added and evenly mixed with the particles to obtain a mixed material; under the condition that air is isolated or inert gas is introduced, the mixed material is carbonized and separated from copper slag after being cooled to the room temperature, and biomass charcoal is prepared; under the inert atmosphere, activator vapor is introduced, the obtained biomass charcoal is activated for 10-120 min at the temperature of 400-800 DEG C, the activated biomass charcoal is dried in air, and the biomass charcoal reduction agent for industrial silicon smelting is obtained. According to the preparation process, the biomass which is rich in source, low in price, renewable and easy to smash serves as a carbon source, and the biomass charcoal reduction agent for industrial silicon smelting has the potentials of being low in large-scale production price, high in yield, high in specific resistance and high in porosity.