Abstract: In order to solve the water flow disorder in the spillway straight line inlet channel guide wall of Sifangjing water conservancy project, the discharge capacity does not meet the design requirements, and the size of the stilling pool is insufficient and the energy dissipation is insufficient when the current discharge design and above floods, we used the method of 1:50 hydraulic model test, the type of guide wall and the size of stilling basin of spillway inlet channel were optimized, and the flow pattern, velocity distribution, discharge capacity and the efficiency of stilling pool in inlet channel were analyzed.The results showed that the guide wall type of straight line + arc could effectively improve the flow pattern and velocity distribution in the intake channel, and significantly improved the discharge capacity of the spillway.After increasing the size of the stilling pool, the energy dissipation rate of the stilling pool was increased by 6% to 9%, and the flow out of the pool was more stable.The research results can provide a reference for similar projects.