Abstract: Centrifugal model tests are conducted to investigate the behaviors of cohesive soil slopes with weak layers under rainfall condition. This study mainly focuses on the soil suction change and deformation process of the slopes. The centrifugal model tests show that failure occurs in the soil slope with a horizontal weak layer, with the slip surface passing through the weak layer. The analysis of displacement and strain of the slope shows that the deformation process of cohesive soil slopes with weak layers under rainfall consists of three stages: uniform stage, dislocation stage and failure stage. During the precipitation process, the pattern of rainfall infiltration can be determined through the strain development of specific points in the slope. The existence of the weak layer, which exhibits significant softening due to saturation and high permeability, causes change in the infiltration distribution and deformation and increases the instability of the slope.