Currently, two types of two-stage mounting system applicable to attenuate vibration of marine machinery equipments are respectively suitable for different conditions.The paper set up the analytical and finite element model of the two-stage mounting system having distributed intermedia mass, analyzing its inherent frequency and characteristics of modal shape, and make a comparison with the two-stage mounting system having frame structure intermedia mass, analyzing the differences about isolation efficiency at different frequency range between the two methods.A scale experimental platform using the two types of mounting system was established to test the isolation efficiency.The research results can provide a reference for engineer to choose appropriate mounting system for machinery equipments.