More attentions have been paid to pentamaran because of their excellent performance.In this paper, a pentamaran composed ofa 3100TEU monohull container ship and four wigley-Ⅲ demihulls is designed, and its seakeeping performance is optimized.Collaborative optimization of seakeeping focuses on demihulls principal dimensions, configuration and main hull form.In this optimization task, pitch, heave and added resistance are the objectives while the total displacement is the constraint.A new method based on the radius basis function for modifying the lines of hull form is proposed and the corresponding code is developed.By the code, automatic modeling and meshing are achieved using command file and calling modeling software PATRAN.The code of multi-hull mesh merging and hydrodynamic computation files updating is also developed for reconfiguration of demihulls.PATRAN and HydroSTAR are combined via optimization tool ISIGHT to establish the pentamaran seakeeping collaborative optimization system based on multiple objectives.The results show that pitch, heave and added resistance of the pentamaran have been improved 8%, 23% and 3% respectively compared to original monohull with the same displacement.