Abstract: High-speed long-distance landslides exhibit complex disaster patterns and diverse triggering factors, making the determination of their initiation mechanisms and dynamic evolution stages a key research focus and challenge. This study takes the Yigong high-speed long-distance landslide as an example and integrates static inversion with dynamic simulation to reveal the triggering mechanism and movement characteristics of the landslide under the combined influence of glacial meltwater and rainfall. Based on remote sensing images, ring shear tests, and digital elevation models, key parameters (pore pressure coefficient) were calibrated using the limit equilibrium method, and a loose accumulation layer was preset along the sliding path to quantitatively characterize shear liquefaction and the scraping effect. The results show that rainfall and glacial meltwater significantly increase pore water pressure and reduce shear strength, leading to landslide instability. Furthermore, shear liquefaction and the scraping effect during motion increased the sliding speed by 32.1% and expanded the landslide scale by 28.3%. The simulation results agree well with actual conditions, providing a scientific basis and methodology for risk prevention and control of similar geological disasters.