The main engine emission of new-type environmentally-friendly rail car carrier meets the requirements of IMO Tier Ⅲ. Taken the type of ship for example, the ship form design and main propulsion system configuration are summarized, the Exhaust Gas Recirculation (EGR), Economical Exhaust Gas Recirculation (EcoEGR) technology, and main engine EcoEGR system selection are expounded, the ballast water treatment technology and ballast water treatment device selection are introduced, and other key technologies are sketched, which provide reference for the development and design of new-type environmentally-friendly ro-ro ferry.