Abstract: A rainfall simulation system in centrifuge is developed to investigate the deformation and failure process of slopes due to rainfall. The system consists of three subsystems: water supply and air pressurizing system, rainfall generator and specialized model container with windproof structure. The system can eliminate influences of the Coriolis force and the high-speed wind on the rainfall. The intensity of rainfall can be adjusted by controlling the air pressure. The validation tests are conducted, and the results show that a uniform rainfall over the whole slope can be yielded by the simulation system. Centrifugal model tests on a cohesive soil slope under rainfall are conducted by use of the rainfall simulation system. The water infiltration in soil during the rainfall is observed to have a significant influence on the deformation and the failure of the slope.