Abstract: Seasonal freeze-thaw is a process that mainly occurs in high latitudes and high altitudes, causing the internal heat and moisture of the soil to fluctuate dynamically with time. Seasonal freezing and thawing changes the physical structure of the soil and reduces the stability of soil aggregates through repeated freezing and thawing; through the leaching and nitrification of the soil, it promotes the release of dissolved organic acids and changes the organic matter in the soil. The content of soil leads to the increase and decrease of soil pH values and the changes of carbon, nitrogen, phosphorus and heavy metal content; the influence of temperature and moisture makes the number and structure of microorganisms in the soil tend to be a dynamic process. Based on the review of the effects of seasonal freezing and thawing on the physical, chemical and biological properties of the soil, it is proposed to strengthen the study of frozen soil in the permafrost regions of the Qinghai-Tibet Plateau, especially the alpine forest line in southeastern Tibet, as well as field monitoring and in-situ research. As well as the study of freeze-thaw soils in a larger-scale soil niche, this is of great significance for the practice of the "two mountains" theory and the construction of ecological security barriers.