Abstract: The step-pool structure is a typical riverbed structure with efficient energy dissipation in mountain rivers, which promotes channel stability by consuming flow energy and increasing resistance. Channel erosion was simulated by flume experiments to explore the mechanism and effect of the step-pool structure on channel stability, to provide a scientific and technical reference for energy dissipation and disaster reduction in mountain rivers. The results show that the step-pool structure can effectively consume flow energy, inhibit sediment transportation and improve flow resistance, thus effectively controlling stream bed incision and slope failure. With the step-pool structure, the Darcy-Weisbach coefficient of the channel increases by approximately 4 times as much as that in tests without this structure, and the time-averaged sediment transportation rate is reduced by 20%—66%, however, the effect of the step-pool structure in stabilizing the channel bed decreases with increasing flow discharge. With same height/length of the steps (0.1), the structure shows a similar effect in improving channel stability. The stability of the step-pool structure is the key condition of channel stability, and it is necessary to prevent the structure from being damaged step by step in practical application.