Abstract: Due to continuous heavy rainfall, landslides were triggered in Biyi Village, Ganluo County, Sichuan Province, resulting in significant property losses. This paper explores the causes of the landslide in Biyi Village by analyzing the local engineering geological conditions, and conducts a true three-dimensional numerical simulations of the entire landslide process using the smoothed particle hydrodynamics (SPH) method. Displacement and velocity monitoring were performed at key positions of the landslide. The results indicate that: (1) unfavorable geological conditions and long-duration, high-intensity continuous rainfall were the main triggering factors of the landslide. (2) The SPH method obtained displacement, velocity, and other motion-related parameters that closely aligned with the actual survey results, demonstrating its good reliability and accuracy. (3) The landslide was caused by the sliding of the rear edge of the landslide, pushing the middle part of the landslide, resulting in overall downward movement and blockage at the front edge, ultimately leading to the formation of a bulging zone. The final landslide failure mode was characterized as a translational slide. (4) The Biyi Village landslide is still in the creep stage. Utilizing the capabilities of the SPH method in simulating large deformations opens up new avenues for research in understanding the mechanisms and engineering strategies for the prevention of similar disasters.