Abstract: In the railway construction within the permafrost region of the Qinghai-Tibet Plateau, due to the complex topography of the plateau mountainous area, there are many pile foundations built in the slope.After undergoing the freeze-thaw process, the soil foundation often causes the pile foundation to tilt, seriously affecting the safety of railway operations.In order to reveal the inclination mechanism of single pile on slope in permafrost area under the influence of foundation frost heaving, based on heat transfer and elastic mechanics, this paper establishes a thermal-mechanical coupling calculation model of pile system and carries out indoor test to verify the rationality of the calculation model.Considering the factors of in-situ frost heaving of foundation soil, water phase change and atmospheric warming, the mechanical characteristics of slope pile foundation under the influence of frost heaving of foundation soil are simulated and analyzed.The research shows that the slope pile is subjected to uneven horizontal frost heave force, horizontal displacement and pile bending moment in the process of foundation soil frost heave, and the horizontal displacement increases with the increase of foundation slope gradient.The pile stress caused by uneven horizontal frost heave accounts for 46.3% of the total stress, which has a great influence on the safety and engineering life of the pile.In this paper, the mechanical properties of single pile under the influence of frost heave of slope foundation soil are analyzed, and the inclination mechanism of single pile under the influence of frost heave of foundation soil is revealed, which could provide some reference for the design and operation of slope pile foundation in permafrost area.