Abstract: Based on EDG-3 SPEY MK202 stressing standards,a main method was presented to study the fatigue life of aero-engine’s principal shaft.In this paper,EGD-3 was used to predict the fatigue life of a turbine runner shaft.So,two methods were used to work out the stress concentration coefficient,one was looking up datum and the other was computed on the basis of finite element method(FEM);whilst the method of stress correction coefficient was used to estimate the low cycle life of shaft,then compared with the nominal stress method.The result shows that it is feasible to estimate the low circle fatigue life of principal shaft using the method of stress correction coefficient;and the result agrees well with that of EGD-3 using the stress concentration coefficient on the basis of FEM under the low cycle load.