To describe the behaviors of vibration isolation, the dynamic models for three types of Passive Hydraulic Engine Mounts (PHEM) were developed in this paper respectively. The state equations were then introduced and solved by means of the Lumped-Parameter method and the Bond Graph procedure. Numerical results were presented for both low and high frequency responses. Then, comparative analyses were carried out. Comparisons showed that the PHEM (with inertia track, decoupler and throttle) behaved the best dynamic characteristics with means of frequency-dependent and amplitude-dependent. The bandwidth of frequencies was also extended to cover high frequencies, which could be the most favorite performance for the researchers and car-manufactures.