The integral model of T root-rim system of the steam turbine blade was established. Moreover

the static and dynamic stress in resonance state of the T-root and root groove were calculated. The high-cycle fatigue safety factor of the T-root groove was analyzed by Goodman method. The results show that

the fillets and the external small angle of the blade root

and the fillets on the end wall and both outsides of the T-root groove are critical areas

which is consistent with the areas of the T-root groove in the failed blade. The proposed method can provide designers with the theoretical basis for designing high-cycle fatigue safety performance of the T-root and root groove

and also provide the operators and inspectors with the critical component of the monitoring and inspection of the T-root and root groove.