Abstract: A general life model adapted to both stress fatigue and strain fatigue is deduced,through analyzing the influence function of strain distribution on life.Strain fatigue and stress fatigue are related by the influence coefficient of strain distribution.This method can be applied to designing sample components for fatigue test as well as to forecasting various fatigue life of component from stress fatigue to strain fatigue.Examples of calculating various typical materials with typical stress concentration are listed in this paper.