Abstract: Based on parameter sensitivity analysis method, the influence of various factors on torsional fatigue property index of turbine-generator shafts was studied. Results show that the tensile strength, size factor and surface machining factor have same sensitivities to the torsional fatigue property index, of which the specific values are all 1. The larger the stress concentration coefficient, the higher the linearity of the sensitivity factor, and when the stress concentration coefficient is larger than 1.68, the sensitivity factor will be more than 1, which will become the main factor influencing the fatigue property. The notch sensitivity factor effects minimum on the fatigue strength. The estimation error of life expenditure may get up to 15.5 times because of the uncertainty of correction parameters.