Biochar has been widely used in soil improvement and carbon sequestration. It has great potential and has attracted much attention in the scientific field at home and abroad.However, the properties of biochar are not only affected by the sources of biomass materials, but also related to pyrolysis temperature and technology.At the same time, different biochar properties and soil conditions also greatly affect the effect of soil improvement and carbon sequestration.In this paper, progress in research on the biochar affecting soil and water environment and carbon sequestration in farmland is reviewed.The study summarize the research achievements of biochar in agriculture, carbon sequestration and reduction, and improvement of saline and alkaline land,analyze the existing problems and discuss the application of biochar in these fields in the future.The purpose of this study is to provide references for the wide application of biochar.