Abstract: According to British standard BS7910 and Europe standard SINTAP, a high-level safety analysis method of pressurized vessels and pipes, leak-before-break(LBB)analysis, is applied into the submarine pipeline in practice.In LBB analysis the determination of some parameters is given, which includes crack opening area, the leakage rate, and through-crack limit size and so on.The result shows that the flaw length at breakthrough, is less than the 110.62mm;limiting length of a through-wall flaw, 27.76mm, and the time to detect the leak is less than the 0.62year for the flaw to grow to a limiting length.So the pipeline meets the LBB condition. The application of LBB makes the safety assessment of pressurized component more scientific and more reasonable.