In order to study the applicability of horizontal swirling flow inner energy dissipation section of spillway section and tailrace tunnel, a new model of flood discharge and energy dissipation is established, namely submerged jet and horizontal swirling cascade internal energy dissipater. The model design of the model test was carried out with the flow rate 1200 m3/s and the maximum total acting head 150 m as the standard. Then the hydraulic model test under the 1∶60.25 geometric scale of the designed energy dissipater was carried out. The results show that when the 1.5<X/D<9.1, swirl hole along the cavity diameter increases first and then decreases rapidly finally becomes steady. When 9.1<X/D<10.3, the cavity diameter increased and finally stabilized to about r/D=0.45. The water level of upstream flow has little influence on the downstream segment of the tailrace tunnel, when the downstream water level is 0.5D<0.85D, the swirl flow and tailwater cave will form a swirling far-flow hydrodynamic regime, and when downstream water level is 0.85D, swirl hole of tailrace tunnel will appear and swirl flow and critical hydraulic jump, when the water level downstream of 0.95D and swirl hole of tailrace tunnel will appear submerged cyclone flow pattern.