Abstract: The turbine unit is an important component in the power equipments, whose dimension and weight will influence the arrangement of power equipments. The optimal design of the turbine unit was analyzed, the mathematic model for the purpose of optimal calculation was established, and the corresponding codes were also developed. The sensitivity of design parameters which influence the turbine unit weight was analyzed in the paper. The present design optimization of the turbine unit, taking the weight minimization as the objective, was carried out with the self-developed complex-genetic algorithm. The results show that the reference turbine unit design is far from the best scheme. In addition, the results also verify the feasibility of the complex-genetic algorithm. Furthermore, the results of this paper can provide reference for the design of the turbine unit.