In order to apply flaring gate pier to the bottom flow dissipation with low Froude number to enhance the dissipation energy,the energy dissipation mechanism and effect were researched through the combination of hydraulic model test and numerical simulation.The calculated result of numerical simulation was in good agreement with the result of hydraulic model test.It was shown that the incomplete flaring gate pier had little influence on the discharge capacity.Besides,the incomplete flaring gate pier did not increase the fluctuating pressure of stilling pool base slab,but increased the velocity gradient in stilling basin to achieve the effect of additional energy dissipation.So that the incomplete flaring gate pier was a meaningful reference to the arrangement of middle and small hydraulic complex.