Abstract: In view of the characteristics of Dashijian Reservoir Project,such as large water level difference between upstream and downstream,wide dam site area and narrow valley in energy dissipation section,this paper adjusts various parameters of the spillway noseway according to numerical simulation analysis and verifies the whole physical model test,and determines that a new type of the spillway is designed with tongue flap-shaped noseway. The experiment shows that the new type of tongue damper can adjust the water drop point through three different radii of tongue,increase the distance of tongue,avoid the concentrated scouring of river bed by tongue,reduce the scouring of foundation of guard tank and scouring intensity of both sides,and achieve the best effect of energy dissipation and anti-scour.