Biochar has a bright prospect due to its good surface properties, pore structure and broad raw materials of its production. It has already been a hotspot in the fields of environment, agriculture and energy. It can be produced from a variety of biomass feedstock, such as agricultural residues, manures, wood, bone and so on, under oxygen-limited conditions. It has great potentials for heavy metal remediation and waste water treatment due to its unique properties, low price, easy processing and wide range of preparation material. The existing literature was incorporated to understand the overall sorption research of heavy metals on biochar adsorbents. However, there was still lack of information on the roles of different sorption mechanisms for biochar. The effects of feedstock materials and pyrolysis temperature on biochar characteristics and metal adsorption capacity were discussed. The interaction mechanisms between biochar and heavy metals, such as ion exchange, complexation, physical sorption, precipitation and electrostatic interactions were analyzed in detail. The influence of adsorption conditions and heavy metal species on heavy metals adsorbed by biochar was also included. At the end, the future research directions on sorption of heavy metals by biochar were proposed. The review would help to build important theory and methodology foundation for directly controlling production and scientific utilization of biochar.