Abstract: The parametric and automation design of Y-shaped crescent rib bifurcation has been discussed.Use the C+ + to develop the program and AutoLisp as the interface to realize the parametric and automation design of Y-shaped crescent rib bifurcation.The test shows that this program can greatly reduce the design cycle of the Y-shaped crescent rib bifurcation.Consequently,this program is of great value in water conservancy and hydropower project design.