In order to improve the energy dissipation rate and increase the aeration, a new type of reverse arc-stepped spillway was proposed, in which the horizontal plane of the traditional right-angle step was changed into a reverse arc surface. The flow pattern, aeration location and energy dissipation rate of the reverse arc step were studied by physical model tests. The results show that in the range of test conditions, the flow patterns of the reverse arc step can be divided into four kinds, which are nappe flow, ejection flow, transition flow and skimming flow. When the length and height of a single step are the same, the aeration position of the reverse arc step is 0. 5 to 0. 8 times of that for a right-angle step, and the energy dissipation rate of reverse arc step is about 9% higher than that of a right-angle step.