Abstract: Although the flow profile is one of the most important parameters to determine the sidewall height of stepped spillway,there is no systematical research result about it.The calculation method of flow profile along steps is proposed,which is based on the theory of non-uniform flow in open channel.The model experiments show that the impact of local head loss should be considered when non-uniform flow theory is applied to calculate the non-aerated flow.The calculated data is consistent with the measured data when the value of local resistance coefficient is 0.5.The flow profile of the flip bucket can be calculated according to the equation which is derived from momentum equation.Also,the equations for computing the flow profile of WES curve segment within the range of 30° and 60° are obtained by model experiments.The results demonstrate that the calculation method for the flow profile of non-aerated flow along the stepped spillway is simple and accurate.