Abstract: The water-surface crossing set, consisted of floating installations, winches, anchors and appendages, can support or append pipeline to cross water obstruction on or under its surface respectively. With good ability of resisting storm and nice reliability, the construction of the set is convenient and rapid. As the.force of flow loads on, via the set, the crossing line, the strength analysis and calculation of the line are important. There are two categories in strength analysis of crossing line, the one in which the line does not bear bending moment may be analyzed as wire rope, and the other in which the line will bear bending moment should be tackled as cross beam. The calculated results show that the crossing span of the former is larger than the latter remarkably.