Abstract: Biochar is a solid, stable and highly aromatic carbon-rich substance produced by pyrolysis of organic substances under anaerobic or anoxic conditions, which exhibits high carbon content, stable chemical properties, large specific surface area and abundant pore structure. Due to its abundant oxygen-containing functional groups, organic anions and inorganic alkali, biochar is commonly used as a soil amendment. This paper briefly described the causes of soil acidification and its related effects, and introduced the types, characteristics and components of biochar. The effects of biochar application in acidizing soil conditioning in recent years were highlighted particularly in increasing soil pH, alleviating Al toxicity, enhancing soil microbial activity and changing the amount of chemical fertilizer. The mechanism involved was discussed. The unsolved problems of biochar in acidifying soil conditioning was finally prospected so as to provide reference for the theory and practice of biochar application in acidified soil.