Abstract: Based on the fatigue failure analysis of marine air bottles， the research on the safety assessment and remaining service life prediction is conducted in this paper. Particularly， the formula to calculate the fatigue crack growth rate is obtained via fatigue crack testing： three typical types of crack on marine air bottles are investigated， and the corresponding safety assessment results as well as the critical crack size are obtained. It is seen that the theoretical formula is valid， and that the air bottle can be safely used till next cycle as long as the initial crack depth a≤1.5 mm， and the length 2c≤10 mm.