Abstract: Design of a component usually involves optimizing its dimensions to meet the operational requirements without failure during the design life. If the operational loads are constant and the operating temperature is not high, a component can be designed for infinite life. However, if the operational loads are fluctuating, they cause fatigue in the component. In addition, if the component operates at high temperatures for very long periods, it may experience creep damage. With the increase of steam turbines steam parameter and the participation in peak-load adjustment of power grid more and more frequently, the stress of the turbine rotor is becoming increasingly complex, and the variable thermal stress has became the major factor reducing its life. We used a 60MW supercritical steam turbine rotor and analyzed the variation of thermal stress in the warm starting-up and cold shutdown process. In this project the analysis based on the operating data measured from actual operation and calculated the variations of the temperature field and stress field during the process of warm starting-up and cold shutdown over a period of 400 minutes with the method of thermal-structure direct interaction analysis by ANSYS.