This paper describes the optimization of the rudder section by the genetic algorism based on VLM(Vortex Lattice Method) and panel method. The developed propeller-rudder analysis program has been validated by comparing with experimental data. The research extends to optimize the anti-erosion rudder section of the large container ship. The object function is the amount of pressure at leading edge of rudder which is closely related with erosion phenomena. The optimized rudder has been compared with conventional rudder with NACA 0021 section by analyzing with the developed program. The finally optimized section has low and mild pressure distribution in comparison with the NACA rudder. The experiments is expected to be carried out for the validation of the present optimization and more parametric study of section geometry is also expected to be conducted in the near future.