Abstract: The curved river channel has a tortuous shape and dynamic characteristics of meandering and creeping.Its formation, development and evolution are complex processes affected by many factors.In order to study the evolution characteristics of curved river channels under water-sediment variation, the natural model method was used to create a relatively natural curved river channel in an indoor flume, and the model test was carried out under two working conditions of whether implementing riverbank protection measures or not.The results showed that under riverbank protection measures, the upstream of the longitudinal section was scoured and cut down, the downstream section didn't change much, the thalweg curvature of the river decreased, and its evolution response characteristics were more sensitive to the variation of sediment concentration.For no riverbank protection measures, the evolution and adjustment of the river channel was strong, and the longitudinal section was integrally incised with larger magnitude at downstream section than that at the upstream section, the thalweg curvature of the river channel gradually increased, and its evolution response characteristics was more sensitive to flow variation.The essence of the curved river channel evolution was the process of mutual adaptation between the water-sediment variation and the river channel morphology adjustment.The final trend of the evolution was that the morphological structure of the river channel and the water-sediment conditions reach a balanced state of mutual coordination.