Abstract: A large number of moraine soil accumulation slopes are widely developed in alpine mountainous areas of China. The slopes are generally characterized by wide gradation,poor sorting and large porosity. Under the influence of complex tectonic geomorphic conditions and freeze-thaw conditions,violent water-heat-mass exchange often occurs and produces ice-rich stagnant water lubrication effect,thus inducing moraine soil interface landslide disaster. The moraine soil interface landslide has great potential risks to the engineering construction in this region. It is the basic work to realize the scientific prevention and control of this kind of geological disasters to systematically grasp the mechanism of hydrothermal migration and frost swelling of moraine soil in alpine mountainous areas. Accordingly,the particle size composition and structural characteristics of moraine soils are studied. The typical "two-grain group" constitutive characteristics of moraine soils are clarified. Then,the current situation of research on hydrothermal migration and frost swelling of moraine soils under freeze-thaw is analysed. The multi-phase multi-field migration mechanism and frost swelling characteristics of moraine soils are clarified. Finally,the study focuses on the evolutionary process of moraine soil slope,and elucidates the causes of the internal ice-rich belt and the mechanism of stagnant water-promoted sliding instability. The study shows that:(1)the typical constitutive characteristics of moraine soils provide the preconditions for the multiphase and multifield migration of water-thermal-mass,and are also the important factors inducing localized freezing and swelling; (2)The oriented interfacial poly-icing phenomenon is produced by the intense hydrothermal migration of moraine soil. The interfacial effect is the source of induced slope instability. To explore the slope instability of the moraine soil,we should focus on the characteristics of the development of ice-rich belt and its pro-slip instability mechanism. (3)The mechanism of disaster generation on moraine soil slopes in alpine mountainous areas is mainly controlled by the following two modes: ① Ice accumulation effect of mixed-state water-thermal migration; ②Stagnant water lubrication effect at the interface of the ice-rich belt. This paper is intended to provide a basic reference for the multi-phase multi-field disaster mechanism of moraine soil slopes in alpine mountain areas.