Soil potassium deficiency has become one of the important factors that affecting crop yield and quality,and limits the sustainable development of Chinas agriculture.It is urgent to further research on how to increase the availability of soil potassium.Therefore,the authors collected and summarized some information about the effects of biochar on soil fertility,especially on the availability of soil potassium.The information showed the research results on how biochar changed the dynamics of soil potassium and improved its bioavailability.The possible mechanisms affecting the availability of soil potassium from several topics including soil temperature,soil moisture,pH,cation exchange capacity,microbial biomass and activity,as well as crop roots activities were discussed,and finally the research objectives that should be focused on was put forward.The paper provided some useful information for promoting the research and application of biochar in future.