Abstract: Centrifuges are the main devices to conduct scaled model tests in the geotechnical engineering discipline, which are widely used in engineering problems such as rainfall and landslides. In this study, a series of centrifugal tests on the motion of unconstrained spheres are carried out. The trajectories of the spheres are reconstructed based on the binocular stereo vision to verify the equations for particle motion in centrifugal hypergravity proposed by Ling et al. On this basis, the numerical analysis is conducted on centrifugal rainfall simulation, and four rainfall uniformity indexes are proposed. It is shown that the coupling of mass changes and non-inertial frame will result in an additional force acting on the object. The spatial and statistical distribution characteristics of rainfall from the Green Mist nozzle can be significantly changed by air resistance and the non-inertial frame forces. The rainfall uniformity indexes have guiding significance for determining the layout of nozzle arrays. Taking the research conditions in this study as an example, for the 2×2 Green Mist nozzle array, the recommended values of the overlap of nozzle coverage area along the length and width directions of the side slope are 60.47% and 55.36%, respectively.