<p>In order to predict the fatigue life of combined sealing ring under pressure pulsation conditions, the fatigue crack propagation characteristic parameters of the materials were determined by Demattia accelerated fatigue tests. Simulation analysis based on the fatigue crack propagation prediction model was carried out to evaluate the stress magnitude and its distribution in the hazardous cross section of the combined sealing ring under pressure pulsation, and fatigue life prediction was carried out for the unit location of the hazardous cross section. At the same time, a prediction study of the fatigue crack formation life of the combined sealing ring was conducted in combination with Fe-safe to verify the reasonableness of the fatigue life prediction model parameters. The results show that the minimum fatigue life occurs in the middle and upper position of the C-ring, and the fatigue life predicted by Fe-safe at the position of the dangerous cross-section is basically consistent with that predicted by the theoretical model, with the relative error within 10%, which provides a methodological reference for the fatigue life prediction of the combined sealing ring under pressure pulsation.</p>