Abstract: Statistics on 203 leakage accidents of submarine pipelines in the Mexico Gulf and China seas shows that the main reasons causing these accidents are the third-party damage, scouring suspension and pipeline corrosion. Causes of the thirdparty damage are analyzed, and countermeasures and maintenance methods are proposed. Submarine pipeline fish-bone diagram model is built, with which the underlying reasons behind pipeline suspension are found out including unreasonable design buried depth, construction buried depth less than required depth, no protection measures, poor construction quality and inaccurate terrain data, and countermeasures are put forward accordingly. It is pointed out that the factors causing submarine pipeline corrosion include failure of anti-corrosion coating, failure of cathodic protection and defects of pipeline itself, and measures to reduce corrosion leakage are proposed. The statistical results can provide a reference to the reduction risk level of submarine pipeline operation and improvement of the daily operation and management and accident reponse ability for subsea pipelines.