Through the model test of stepped spillway,the paper verified the flow capacity of side weir and studied the change rule of velocity, pressure and water depth of typical cross-section under different conditions.The test results show that the flow capacity of side weir meets the design requirement, and the water depth is less than the design height of side wall. The cavitation number in each point is less than the initial cavitation number which will not cause the cavitation erosion. According to original design,the paper used FLUENT software to conduct numerical simulation test for stepped spillway,and compared the result of numerical simulation calculation with the result of model test.The coincide of two results is very good.The result can provide the possibility for depth analysis of flow field of stepped spillway steep slope and offer the technical support for body structure optimization.