Abstract: With the constant development of modern marine technologies, the vessel energy now can be distributed through an Integrated Power System, which is known as the third vessel power revolution. In this paper, the technical features of the first and second generation integrated power system are introduced. Next, based on the present domestic technical status, the research progress of the quasi second generation medium voltage DC integrated power system in China is presented, with the corresponding difficulties and problems analyzed, including the system model, electrical-magnetic transient simulation, the connected op-erator between the gas turbine generator set and the diesel generator set, the system steady analysis, and system layered protection. Finally, the solutions are proposed, which indicates that the development are re-quired on the medium voltage DC breaker, system energy storage, system safe operation, multi-time scale, and multi object system energy regulation.