Abstract: This paper describes our variable amplitude LCF life prediction system based on the strain fatigue theory.The local stress strain method modified by us is more accurate than the conventional local stress strain method,This method is provided for disk life design.The presented system is also capable of accurate prediction of the variable amplitude LCF life according to the statistic data of smooth round bar specimen LCF lives to failure,so it is quite a convenient and simple experimental estimation method.Finally,the new method used in the presented system for detemining the reliability life of rotating disks is better than the method in EGD 3 stress standard.