In this paper，the effect of flexible supporting propulsion system on the vibration noise of propeller-shaft-hull coupling system is studied. A numerical model of the flexible supporting propeller-hull coupling system is established. The vibration and radiated noise of the hull under the longitudinal，horizontal and vertical excitation of the propeller are calculated using finite element/boundary element method，and are compared with the traditional support system. The results show that the large radiation noise of the hull is mainly caused by the coupling mode of shafting and raft frame，and it is beneficial to reduce the radiation noise of the hull by improving the mass and stiffness of raft frame. Compared with the traditional support，the flexible support can significantly reduce the radiated noise of the hull，which is reduced by 14.65 dB under the longitudinal excitation，4.48 dB under the horizontal excitation，and 8.36 dB under the vertical excitation. The use of flexible supporting propulsion system can reduce the hull radiated noise and provide support for vibration and noise control of propeller-shaft-hull coupling system.