This paper presents a new control method for a super-turbo generating (STG) system using an accurate ship-plant system model that ascertains startup characteristics. The STG system is a waste heat recovery type of generation system that makes use of exhaust gas from the main shipboard diesel engines. With STG systems, however, control during startup is not entirely clear. Startup characteristics from the steam turbine and power turbine startup through synchronization to the system bus are ascertained using an accurate simulation model, and the startup sequence control is clarified. As a result, the startup sequence control under consideration facilitates a safe and smooth STG system startup. Synchronization to the system bus is attained, and highly satisfactory results are achieved, while avoiding the risk in actual plant testing.