Abstract: The expansive soil is a kind of high plastic clay rich in montmorillonite, illite and kaolinite, in which volume expansion will occur under humidification. If the lateral swelling deformation is constrained, the horizontal swelling pressure will be generated, which will cause great harm to geotechnical engineering facilities. In recent years, in order to reduce the relative losses, domestic and foreign scholars have performed a large number of laboratory tests and developed new theoretical methods and prediction models for horizontal swelling pressure. The influence factors of swelling characteristics of expansive soils and the influence laws of various factors on the swelling characteristics are analyzed, and the influence mechanism of various factors is studied from the perspective of microstructure. Finally, the practical measures to reduce the lateral horizontal swelling force are proposed, the importance of studying the horizontal swelling force of fissured expansive soils is analyzed, and the future research direction is prospected.