A twostep optimization method was presented to improve the aerothermal characteristics of turbine blade airfoil. The first step was to construct turbine airfoil by polynomial lines. Design parameters were screened by design of experiment (DOE) and factorized sensitive analysis for best performance obtained from CFD simulations. The second step was to optimize airfoil

which was parameterized in Bezier lines for minimum flow loss and surface heat transfer in a weighted objective function. Result of design sample shows that increased stagger angle leads to lowered heat transfer along the pressure side surface

and larger leading edge radius reduces the local heat transfer around stagnation point. Reforming the polynomial shaped airfoil provides possible delay of the transition on the blade suction side surface and reduces whole heat transfer rate. Twostep method has relatively low computation requirement and good convergence

which is valuable for engineering purposes.