Abstract: Finite element calculations were carried out on an ultra-supercritical steam turbine valve to obtain the distribution of its temperature and Mises stress in startup, stable operation and shutdown processes using Abaqus software, while the results taken from characteristic positions were adopted to implement the damage and life assessment under the interaction of fatigue and creep by applying the damage assessment process in R5 procedures. Results show that the valve has remarkable creep behavior in operation period; great local stress appears in some areas of the valve, and the Mises stress varies greatly in different stages; the single cycle damage at most dangerous position of the valve is 0.014 07, securing the safe operation of the valve for 70 cycles.