Abstract: This paper studies the solidification mechanism and identificates the chemical reaction between SH agent and clay minerals. It carries out the X-ray diffraction test, infrared spectrum test, microscope and polarizing microscope observation, and scanning electron microscopy detection, respectively, on clay minerals(montmorillonite, kaolinite), quartz, saline soil and theirs solidifying one with SH agent. At the same time, in order to evaluate the effect of solidification, it carries out the mechanical tests and freeze-thaw test on solidified lime-saline soils and SH agent-lime-saline soils. The results show that XRD spectrum and IR spectrum of the solidified materials are generally consistent with one of original materials, and the mineral composition is not changed. The functional groups of SH agent are not combined with the clay minerals, and no new substance is generated. SH agent produces an elastic and three-dimensional network and the silk fills the pores, and the soil particles are bonded in a whole, which increases the strength and decreases pore ratio of solidifying saline soil. Meanwhile, because of SH agent wrapping soil particles, the adhesive force and hydrophobicity of soil particle are increased. The results of the mechanical tests on SH agent-lime-saline soil have proved that SH agent can improve the strength in air and water, deformation resistance, anti-permeability of saline soil. The results of freeze-thaw experiments confirm that the three-dimensional network and the silk can partly resist the expansion and contraction of soil during freezing and thawing, and weaken the structural damage of soil. Therefore, the addition of SH agent is helpful to enhance the freeze-thaw resistance of solidified soil. SH agent does not generate chemical reaction with clay minerals. The improvement on the mechanical properties of saline soil mainly depends on the physical effect between SH agent and soil particles.