Torsional vibration model of turbine-generator shafts is the basic for fatigue life loss analysis, for the accuracy of the fatigue analysis of the shafts depends on the precision of the inherent characteristics of the shafts model. The sensitivity of the inherent characteristics of the torsional vibration model to the structure parameters of the turbine-generator shafts is analyzed in this paper. A parameter adjusting method for the torsional vibration model is proposed based on the method of Taylor expansion. The logic structure of the adaptive process of torsional vibration model is designed. The torsional vibration model for a 1000WM turbo-generator shafts was taken as an example and the accuracy of the method is verified.