Abstract: Many factors shall be considered in terms of stress analysis of offshore pipelaying, including the curvature and length of pipe carrier, the tension and buoyancy on pipeline, pipe coating, and the mdeium to be transported. It is especially the case when pipe laying barge is used: The moment of flexure in pipe is considerably large because of the big pipe length suspended in the sea; Also non-linear stress occurs due to large turning moment in pipes. Therefore, it is necessary to calculate accurately pipe deformation, load and stress, to apply moving coordinate in the stress analysis for offshore pipelaying, and to use the iteration method of "contact" and "relaxation" to solve the contact between pipeline and seawater. The results show that this method can quickly converge into the requirements for engineering analysis.