Biochar has great influence on global carbon biogeochemical cycle as well as climate change.It is believed that biochar should be an important pool of atmospheric CO2.Researches have showed that the application of biochar is of great importance in increasing soil carbon storage and have influences on soil ecosystem by improving soil physicochemical properties，improving soil fertility and immobilizing or absorbing soil pollutant.In this paper，the main characteristics of biochar were stated，the current research results on applying biochar to soil was discussed，the advantages of biomass derived black carbon return to croplands were evaluated，and the key problems in further research were put forward.