A new method for confirming the fatigue damage curve was presented.Based on the situation that the strength of structure of vehicle descends after originally arising,the method can provide more precise accumulated fatigue damage of vehicle parts under certain load spectra.In order to get the modified damage curve,the primitive stressnumber of cycles curve(S-N curve) was rotated around the original point and presuming that the slope of S-N curve be k,2k/3 would be adopted as the slope of the new S-N curve.Reasonable explanations for the damageaccumulations of parts under cyclic loads of level 2 were presented.