Abstract: A new structural fatigue life prediction method is presented in this paper.Nominal stress spectrum, stress severity factors and constant life curves according to nominal stress for a structure are known. The curves can be changed into the structural constant life plots of local stress（strain） , then the structural life is estimated in accor-dence with calculated local stress-strain histories and the plots. Still calculated local stress-strain histories can be changed into nominal stress histories, then the structural life is estimated, by means of the structural constant life curves according to nominal stress.The method has the advantage of nominal stress method and local strain method to counteract themselves weakness.