Abstract: Aiming at the energy dissipation problems of large unit width flow and low Froude number in the original design scheme of the stilling pool of a hydropower station, the body size parameters and the number and position of auxiliary energy dissipators were optimized through physical model test, and the flow pattern and the hydraulic characteristics of each scheme were compared and analyzed. The test results show that the combined energy dissipation scheme of excavated stilling pool and energy dissipation piers（digging 4.20 m down and setting the energy dissipation piers） can effectively stabilize the flow pattern, diminish the amplitude of water level fluctuations, significantly reduce the flow velocity out of the stilling pool, and achieve significant energy dissipation effects.