In this study, the changes of heat transfer characteristics of single crystal blades were studied in numerically by operating points according to the gas turbine start sequence. The operation sequence of the target gas turbine was analyzed to select the start sequence, and each operation point was divided and analyzed based on the operation condition at the corresponding point. As a results, the ambient temperature varies from one operating sequence to another, which causes a change in the heat transfer characteristics to the blade surface. It is considered that the result of thermal fatigue will affect the start sequence.