Abstract: On the basis of the -N curved surface, the fatigue life of turbine disk is investigated in this paper by constructing Goodman and Gerber types of generalized -N curved surface equation based on stress amplitude and mean stress. An example of an aircraft engine turbine disk is presented to validate the proposed method, and the results show that the prediction from Goodman equivalent life curve is much better than that of Gerber type model. In addition, there is no need to equivalently convert the cyclic stress in above method. This method can improve the accuracy of fatigue life estimation.