The reasonable design of discharge and energy dissipation facilities is of great significance to ensure the safe operation of water conservancy projects.According to the design data of a reservoir，the hydraulic test model is made，and the structural design of spillway is optimized by the method of model test.The research results show that the discharge capacity of the original design scheme of the spillway can not meet the design requirements，the height of the side walls of the first and second stage steep slopes is low，the margin is obviously insufficient，and there is a relatively obvious negative pressure area on the back slope face of the labyrinth weir.According to the original design scheme，the optimization scheme is proposed to increase the total width of labyrinth weir，shorten the length of steep slope section，increase the height of side wall of steep slope section of spillway，reduce the width of chute inlet and increase the length of flip bucket.The model test results show that the flow capacity and the height of the side wall under the condition of the optimized scheme meet the flow requirements，there is basically no negative pressure along the way，the cavitation effect can be ignored，and the downstream scouring will not have a significant negative impact on the operation of the project， fully meeting the design requirements， which is recommended to be used in the engineering design.