Abstract: Multi-state marine vehicles (MSMVs) are capable of switching among different navigation states such as surface, semi-submersible, and underwater, representing a novel category of marine equipment developed to meet the demands of complex sea conditions and multi-mission operations. Centering on navigation-state transition principles and combinations, this paper reviews typical MSMVs both domestically and internationally, and categorizes their technical routes into three types: static, hydrodynamic, and hybrid cooperative approaches. It then surveys the research progress of key technologies with respect to overall configuration, hydrodynamic modeling, structural materials, energy and propulsion, maneuvering control, communication and navigation, and autonomous decision-making. On this basis, major bottlenecks are summarized, including cross-state modeling and control under complex sea conditions, low-speed and zero-speed state transition, deep-sea pressure resistance and dynamic sealing. Furthermore, key research directions are proposed, such as mechanism-data fusion modeling, hybrid cooperative control, and improvement of structural and mechanism reliability.