Abstract: A united optimum method for designing an axial turbine stage is provided which combinesthe blade geometry optimization with the optimization of meridian passage according to the blade twist. The physical models,mathematical expressions and procedures for optimum selection of the blade geometry, meridian passage and its twist are described respectively, and then a united procedure is proposed. A numerical example has been calculated with this procedure.In the result,this method is proven of both theoretical and practical values and may furnish the basis for CAD of a turbine stage.