Abstract: With the development of Chinese economy, the demand for natural resources in coastal cities is growing day by day, and it is of great significance to use superlong pipeline to transport natural resources across the sea to support economic development and construction of coastal cities. However, the design and laying of super long cross-sea pipeline mainly rely on experience and engineering analogy method. In order to provide sufficient scientific basis and measured data support for the floating process of offshore ultra-long pipeline, this research team carried out a fluid-structure coupling numerical simulation study on the floating process of offshore ultra-long pipeline based on the pipeline floating construction project in Tongan Bay, Xiamen, to obtain the deformation characteristics of the pipeline floating and apply them. The results show that the strain and displacement of floating pipelines are directly proportional to the slenderness ratio of pipelines and the relative velocity, and inversely proportional to the number of tugboats and the bending angle of pipelines. The maximum displacement of tugboat decreases by about half with each additional tugboat. Changing the number of tugboats or the towing force can effectively control the deformation of the pipeline. The calculation and analysis of the resistance and deformation of pipeline floating transportation is conducive to the reasonable arrangement of tugboats and the safety of pipeline floating transportation. When the wave and current are combined, the pipeline deformation is large and the floating transportation should be carried out when the sea wave is small.