Abstract: Free span of submarine pipeline is a very common and urgent problemto be solved in offshore oil pipeline engineering. Traditional measures for free span are introduced in this paper, such as filling sandbags, coverage of "bionic plants", grouting and fixed support method. The principle and construction process of cantilever support method are presented. The problem of free span can be solved for good in the life cycle of the pipe through mounting support structure on the bottom of the subsea pipeline and fixing it to the seabed with suction pile. The cantilever support method has been applied to Ledong Gas Pipeline. The result shows that the construction process of cantilever support program is simple, without disruption to oilfield production, and highly reliable. In addition, it has great application advantages in both cost and effectiveness. This method can provide a reference to the deepwater submarine pipeline free span.