【Research Purpose】: The vibration of steam turbine units is transmitted to the ship through the connecting structure of the ship, stimulating the vibration of the ship, and even causing fatigue damage to key components. The prerequisite for vibration reduction and noise reduction of steam turbine units is to analyze the mechanism and transmission path of vibration and noise, thereby reducing the vibration amplitude, and improving the working efficiency of steam turbine units; In conventional vibration analysis of ship structures, excitation source data is usually obtained using experimental or empirical formula methods, which may result in computational analysis errors. 【Method】: The multi body dynamics method was used to accurately analyze the mechanical vibration excitation sources of steam turbines. The results of excitation source analysis were used for the first time to study the vibration response under low-frequency excitation. ATV was used to describe the sound pressure contribution of the calculation unit of the sound field system. From the perspective of multi body dynamics and the method of fluid structure coupling, the mechanism of vibration and noise generation in steam turbine units was comprehensively analyzed, and typical transmission paths of noise were studied, providing reference for vibration reduction and noise reduction. 【Result】: The research results indicate that the rotating excitation source is the main vibration excitation source of the steam turbine unit. From the polar plot of noise radiation directionality, it can be seen that the noise directionality is similar at different heights, and larger noise sound pressure levels are obtained in the length direction, indicating strong directionality. 【Conclusion】: The research method has certain guiding significance for the vibration reduction optimization design of steam turbine units.