In terms of the special situations of poor water quality, more sediment, and the annual marine-fresh water alternation in the port of a rail car carrier route, the electrolytic ballast water treatment plant and ballast water treatment system which can add the high-salinity marine water are selected. The elimination method is used to analyze and confirm the selection of ballast water treatment plant and the related design modification and optimization of ballast water treatment system in the carrier, so as to make the carrier realize the ballast water operation of discharging while ballasting in the marine water port or turbid fresh water port, which can provide valuable reference and lessons for the design of ballast water treatment system in the future possible subsequent or similar forms.