The distribution and migration processes of microplastics (MPs) in rivers—such as aggregation, horizontal transport, and subsurface flow exchange—are systematically reviewed. As a persistent pollutant, microplastics (MPs) are difficult to degrade and can exist for a long time after entering the environment, causing negative impacts on the ecological environment. Based on the data of abundance, shape, size, color and composition of MPs in Marine, river and lake water, environments—drawn from representative domestic and international literature, the occurrence characteristics of MPs in domestic and foreign water bodies are comprehensively analyzed. The widespread presence of sediment in rivers can affect the migration of microplastics. This study further examines the migration of microplastics in sand-bearing rivers, including the aggregation and co-sedimentation of microplastics and sediment, the influence of sediment on the re-suspension and permeation process of microplastics, and the interaction mechanism and influencing factors of microplastics and sediment. It is suggested that future studies of microplastics transport in sediment-bearing rivers should focus on the development of reliable models to predict microplastics migration and flux, and the effects of biological and water disturbance on the transport of aging microplastics should be considered in laboratory simulations.