AbstractThe small sample data under the highest stress level are augmented based on the improved Bootstrap method, and then the augmented data are converted to sample data under the lower stress levels with the Principle of Fatigue Life Probability Percentiles Consistency. Furthermore, the augmented sample data and the original data are fused into the equivalent large sample data to establish the P‐S‐N curve with higher accuracy. Meanwhile, a new method for calculating the fatigue damage parameter of the notched specimens is proposed based on the two‐point method. A modified P‐S‐N curve is established to predict the fatigue life of other specimens with different stress concentration coefficients under different stress levels. In addition, the experimental data of three kinds of materials are collected to verify the feasibility and accuracy of the new method. The results show that the predicted fatigue life is in good agreement with the experimental life.