In response to the threat that slope collapses in mountainous areas pose to the safety of rural infrastructure, a typical landslide in Anhua County, Hunan Province is taken as the research object. By combining dry-wet cycle simulations and laboratory geotechnical tests, numerical simulations of high-risk slopes are conducted based on a constitutive model, in order to explore the mechanism of instability under the influence of dry-wet cycles. The results show that as the number of dry-wet cycles increases, soil parameters decrease and shear strength declines, indicating the internal mechanism by which the alternation of dry and wet conditions in the local climate causes landslides. When there is no dry-wet cycle, the slope safety factor F_s is 1.05, indicating a critical stable state; areas of concentrated shear stress and localized high-plasticity zones appear within the slope and at the foot of the slope. After the first to third dry-wet cycles, F_s drops to 0.91, 0.88, and 0.85 respectively, with the largest decrease occurring during the first cycle, the subsequent decline becomes more gradual. Considering factors such as safety, economy, and construction convenience, the use of circular anti-slip piles for reinforcement can effectively improve the safety and stability of slopes. The results can provide a theoretical basis and reference for the intelligent prevention, control, and risk management of slope collapses in tropical monsoon regions.