The invention discloses a method for preparing conductive carbon using biomass, which comprises the following steps: performing low temperature carbonization of biomass; preparing catalyst using nickel oxide or iron oxide as main catalyst and CaO and CaCO3 as catalytic promoter; mixing with carbon powder after low temperature carbonization; performing high temperature carbonization. Compared withthe prior art, the method for preparing conductive carbon using biomass has the advantages of good adaptability to material, wide application range in agricultural straw, forestry scrap, bamboo and industrial biomass waste, low energy consumption during preparation, low final carbonization temperature of only 800 to 1000 DEG C (about 200 DEG C lower than the prior art), capability of saving energy consumption of over 20%, low resistivity of 0.01 to 0.5 R x cm, and stable quality.