The potential carbon sequestration ability of biochar was investigated. The results indicated the amendment of biochar to soil could reduce the CO2 emission and increase the organic matter of soil effectively. The influence extent enhanced as the increase of biochar and the influence extent on soil with lower organic matter content is much obvious than soil with higher organic matter content. After incubated 7 months, soil CO2 emission was suppressed significantly by the amendment of biochar. The CO2 release amount in soils with 8% biochar decreased 29%∼39% compared with control. Organic matter content in soils with 8% biochar increased 41%∼75%. In addition, biochar promoted the formation of soil aggregates. Mean weight diameter of micro‐aggregates in soils with biochar increased obviously compared with the control, indicating that stability of soil aggregates improved as the increase of biochar. The research demonstrated that biochar had potential ability on soil carbon sequestration, which was realized by enhance organic matter content, suppressing CO2 release and improving micro‐structure characteristic of soil. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 941–946, 2014