Abstract: Centrifuges are the main device to conduct scaled modeling tests in geotechnical engineering disciplines, which is widely used in engineering problems such as rainfall and landslides. In this paper, a series of centrifugal tests on the motion of unconstrained spheres are carried out to verify the equations of particle motion in centrifugal hypergravity. Furthermore, the equations are extended to account for changes in particle mass to simulate the rainfall in centrifugal hypergravity field. The extended equations indicate that the mass change of an object in a non-inertial frame introduce an additional force. Numerical analyses are conducted for the nozzle-type centrifugal rainfall simulation base on the equations, and four rainfall uniformity indicators were proposed. The analyses reveal that air resistance and non-inertial frame forces can significantly alter the spatial and statistical distribution characteristics of rainfall from a nozzle. For the 2 ×2 Green Mist nozzle array, the recommended values for the overlap of nozzle coverage area along the length and width directions of the side slope are 60.47% and 55.36%, respectively.