Landslides caused by snow melt and rainfall in the seasonal freezing area pose a great threat to the construction and maintenance of highway transportation infrastructure, this study is based on a highway project in the Yili region of Xinjiang, for which a site survey was conducted and a monitoring station for 6# landslide of a highway in Xinjiang was established, by establishing a monitoring station, information such as displacement, moisture and temperature of this slope was monitored, using this monitoring station from November 2019 to August 2020 for the whole freeze-thaw period, and also based on the unsaturated soil analysis of geostudio software, the numerical simulation of soil moisture content change was fitted with the field monitoring data, and an effective numerical method was established, and the stability of this slope under the influence of seasonal permafrost freeze-thaw during the snowmelt period was analyzed, and the relationship between the moisture content change of the surface slope soil and the stability of the slope during the snowmelt period was studied, and according to the The initial sliding of the landslide was analyzed according to the model established. The results show that: snowmelt water plays a dominant role in the change of soil water content - snowmelt water and frozen stagnant water infiltrate along the fracture advantage, increasing the soil water content at the beginning of the snowmelt period and increasing the self-weight of the soil; maintaining a higher soil water content during the snowmelt period, and with the occurrence of continuous rainfall, the wetting front moves down, the soil pore pressure increases, forming a transient saturation zone and Slope destabilization. The long-time rainfall during the snowmelt period is an important reason for the occurrence of this landslide. The method of fitting the numerical simulation of soil water content changes with the field monitoring data and performing slope stability analysis on this basis has high credibility and can provide reference for landslide warning after this area.