This chapter begins by outlining the research background of rainfall-induced landslides. It focuses on two critical issues in this field, namely the heterogeneity of slope geomaterials and the influence of water-induced weakening effects in soft rock on slope stability during rainfall. The discussion then turns to the limitations of widely adopted GIS-based methods for regional-scale analysis of rainfall-induced slope stability. Drawing on this background, the chapter presents a literature review that synthesizes previous studies and highlights key developments in the analysis of slope stability under rainfall conditions. The review covers three main aspects, including two-dimensional (2D) and three-dimensional (3D) slope stability analysis under rainfall conditions, and regional-scale assessment of rainfall-induced landslide susceptibility.