Aiming at the research progress of biochar as a new type of soil amendment, the preparation method of biochar was introduced. The mechanism of biochar and soil heavy metals was analyzed, and the biochar hyphenated technology was discussed. It is concluded that the raw materials, pyrolysis temperature, pyrolysis time and other preparation conditions have varying degrees of influence on the removal of heavy metals by biochar. The pyrolysis temperature has the highest influence. The biochar can be prepared by optimizing the pyrolysis temperature and other conditions. There are two action modes between biochar and soil heavy metals: direct and indirect. The mechanisms between different biochar and heavy metals are different. It is necessary to study the mechanism and select the appropriate biochar. Compared with the application of single biochar, the synergistic and remediation effect of biocharcan be improved by combining with alkaline substances and composting technology.