Abstract: In order to fully understand the engineering characteristics of expansive soil and find out a reasonable treatment scheme for expansive soil, the expansion experiment and shrinkage experiment based on load are carried out. The results show that the expansion rate of soil sample is the largest when there is no vertical load. A large enough load can control the expansibility of expansive soil. The dry density of soil samples is proportional to the vertical load. There is also a control inflection point in the relation curve between load and soil sample shrinkage.