Abstract: Lime，cement，fly ash，and weathered sand were used to improve the same kind of expansive soil． After mixed with different proportion，indoor experimental test was done． Through which it could be seen that those four kinds of materials could improve the shear strength of the expansive soil． The cohesive force and internal friction angle of the mixed cement expansive soil could be greatly improved． Followed by mixing lime could also significantly increase the shear strength of expansive soil indexes． After incorporating weathered sand and fly ash，the expansive soil cohesive force would be declined． With the increasing of dosage，internal friction angle was first gradually increased，then decreased slow down． The four kinds of materials could effectively improve the expansion properties of the expansive soil． From the effect of the influence of load swelling ratio，mixing lime had the best effect to curb inflation，followed by cement，the next was followed by fly ash and weathered sand．