The effects of polymer active agent content and curing time on the mechanical properties and salinity changes of sulfate saline soil were investigated by triaxial shear test and soluble salt content test. The microscopic characteristics and improvement mechanism of CLI polymer active agent surfactant were also investigated. The results show that the addition of CLI polymer active agent can effectively improve the mechanical strength and anti-deformation ability of sulfate saline soil， and its optimal dosage is 8%. The pores are filled by the displacement reactions between CLI polymer active agent and the saline soil， improving the water retention performance. It can also effectively reduce the soluble salt content in the saline soil. The higher the CLI polymer active agent content， the better the improvement. The soluble salt content tends to be stable after 7 days.