The fatigue performance of cylinder head material was tested based on the sample extracted from the cylinder head. A new selection method of fatigue life distribution model was proposed. Lognormal distribution model was adopted in high stress and low cycle life zone. Three parameter Weibull distribution model was adopted in low stress and high cycle life zone. MATLAB calculating parameter method of three parameter power function S-N model was given and the fitting errors of different S-N fatigue stress life models were analyzed. The results showed that the accuracy of three parameter power function model was better than the other two models. Finally, the fatigue strength was predicted according to the calculation results. The smallest deviation between predicted result of hybrid life model and test result of up-and-down test was 6 MPa.