<p>Rainfall and in-situ leaching, a mining process involving the injection of chemical solutions to extract rare earth elements, are the two primary triggers for landslides in ion-absorbed rare earth deposits. While previous research has often treated these factors in isolation, this study specifically investigates their coupled effect. We developed a numerical model to simulate slope seepage and stability, employing the finite element method for unsaturated seepage analysis and the limit equilibrium method for stability calculation. The model was used to determine rainfall intensity-duration (ID) thresholds for slope failure under varying durations of leaching cessation prior to rainfall. The results demonstrate that a longer interval between stopping injection and the onset of rainfall significantly enhances slope stability. Furthermore, we identified that high pore water pressure is a critical failure mechanism. Consequently, a novel landslide early warning model was established based on quantitative pore water pressure thresholds, which can be categorized into different warning levels. This model provides a practical and scientific framework for mitigating landslide risks in rare earth mining areas, enabling a better balance between safety and production efficiency.</p>