Abstract: The rapid development of freeze-thaw desertification poses a serious challenge to the ecological security of Qinghai-Tibet Plateau. In order to improve the research level of freeze-thaw desertification and promote scientific prevention and control of freeze-thaw desertification, the authors took freeze-thaw desertification of Sanjiangyuan region as the study object to construct a remote sensing investigation method for freeze-thaw desertification based on geological features. The freeze-thaw desertification in Sanjiangyuan region was studied by this method to analyze its spatial distribution characteristics, the causes and the development trends of freeze-thaw desertification. The results show that the types of permafrost landforms formed in different geographical locations in permafrost distribution areas were the basis for interpreting freeze-thaw desertification and the freeze-thaw desertification was divided into three levels, that is severe, moderate and mild, combined with comprehensive indicators of proportion of exposed surface and fragmented areas, vegetation coverage, and surface landscape characteristics. The remote sensing interpretation indicators for different degrees of freeze-thaw desertification were constructed, and the interpretation accuracy of freeze-thaw desertification in Sanjiangyuan region was over 80%. The study area was dominated by severe freeze-that desertification, and Yangtze River source region has the largest distribution area of freeze-thaw desertification in Sanjiangyuan region. Permafrost was the material condition for the occurrence of freeze-thaw desertification, and the sustained warming of regional climate was the internal cause of the exacerbation of freeze-thaw desertification. And overgrazing and overloading were the main human activity influencing factors that cause the rapid development of freeze-thaw desertification. Due to the warming and humidifying trend of Qinghai-Tibet Plateau climate, the continuous degradation of permafrost will further exacerbate freeze-thaw desertification. The relevant research results indicated that remote sensing survey methods could achieve rapid acquisition of information on freeze-thaw desertification, which has certain reference significance.