Abstract: On the basic research of hydraulic characteristics of the compound expression spillway tunnel of inner energy dissipation with vortex-flow block and vortex-flow divergent, when the diversion tunnels are reconstructed from Lianghekou Hydroelectric Station and Houziyan Hydroelectric Station, the principle and method of hydraulic design are researched,and the type of the open intake,vortexflow generator, block and vortex-flow gradually expanded section are designed and calculated. The result offers a reference about hydraulic design in which the diversion tunnel will be reconstructed as a vortex-flow spillway tunnel with discharge more than 1 000m³/sand available pressure head 150 m.