Abstract: Optimization design method was used to optimize the flow-path modeling of one turbine stage.The parametric modeling method based on non-uniform rational B-spline(NURBS) technology was used for turbine stage flow-path parametric modeling.The maximum isentropic efficiency and minimum temperature at rotor hub of the leading edge were selected for multi-objective optimization design.Combinatorial optimization strategy based on parallel sub space was introduced for the large-scale and multi-objective optimization so as to improve the efficiency of the optimization and shorten the design cycle optimization.Optimal design of the turbine-efficiency was improved by 0.664%,the maximum temperature at rotor hub of the leading edge dropped within the range of 1.5%.This work shows that this design method of turbine design is of great value.