The aerodynamic optimization for turbocharger turbine blade is studied using variable dimensionality analysis technology. The aerodynamic optimization procedure is decomposed to two steps: two-dimensional (2D) optimization and three-dimensional (3D) optimization based on the 2D optimal results. The quintic polynomial method with continuous three order derivatives is used to present section profile of three sections, root, middle and tip of blade. The 2D aerodynamic analysis and optimization are carried separately for different sections. Aerodynamic optimization for turbine blade is driven by the combination of global and local optimization arithmetic, with the 2D optimization blade as initial value, and profile parameter as design variable. The result shows that the calculation time is shortened and the optimization efficiency is improved, compared with the full 3D optimization under the same effect.