A steep wave configuration design is taken as the research object, the drift domain of the floating body on the ocean surface, the maximum curvature of the pipeline and the economy are taken as the design indexes. The numerical model of the flexible riser configuration is established, and the sensitivity of the three indexes to the number of buoyancy modules is analyzed. The minimum drift domain, maximum configuration curvature and minimum cost are extracted as the optimization objectives with the normalization processing. The multi-objective optimization design of the number of buoyancy modules of the flexible riser with steep wave configuration is conducted and the best design is obtained.