Abstract: The paper mainly analyzes three lumped parameter (LP) models of passive hydraulic engine mounts.There are three passive hydraulic engine mounts: HEM with only one inertia track, direct-decoupler hydraulic mount and direct-decoupler hydraulic mount.The paper introduces the apparatus used for obtaining and identifying the parameters of the three lumped parameter (LP) models and also introduces the method of parameter estimate.Comparison of dynamic stiffness and phases characteristics of three passive hydraulic engine mounts among them in the low frequency domain (0~50Hz) and high frequency domain (50~250Hz) is conducted.The results obtained show that the dynamic stiffness of the HEM with only one inertia track is the highest.In the low frequency domain, the dynamic stiffness of floating-decoupler hydraulic mount increases faster than that of others.The characteristic of 'hard' and 'soft' in the low frequency domain and high frequency domain is distinguished among the three mounts.