Abstract: The rapid expansion of highway construction in mountainous areas has heightened the focus on the stability of dumpsites and the assessment of potential failure disasters. High-energy landslides can severely impact structures along the way, posing significant risks to life and property. Leveraging the material point method (MPM) for simulating large deformations in continuous media and the discrete element method (DEM) for precise contact detection, the MPM-DEM coupling algorithm can effectively models interactions between landslides and complex terrains or structures. This study employs the MPM-DEM coupling algorithm within the GPU-accelerated high-performance computing software CoSim to analyze the stability and dynamic hazard potential of dumpsite slopes. The validity and accuracy of the proposed algorithm were initially verified through a case study involving granular material impacting a structure. Subsequently, a highway dumpsite in Yunnan Province was selected as an example to evaluate the stability factor and the predict the potential failure’s impact range and severity. Results indicate that the dumpsite slope is currently stable; however, should instability occur, it would exert significant impact on downstream highway bridge piles. The numerical simulation results demonstrate the strong capabilities of the coupling algorithm in the stability and dynamic failure analysis of dumpsite slopes, which can simulate the entire process of "stability-large deformation-flow-accumulation" for slopes.