A new type of vibration isolator is proposed by using a two-layer variable-bar length X-type mechanism in order to achieve the design objectives of the isolator with low dynamic stiffness and high damping. Firstly, the harmonic balance method is used to obtain the stationary analytical solution of the established mechanical model for the vibration isolation system, and the amplitude-frequency response, phase-frequency response, equivalent stiffness, equivalent damping and force transfer rate of the vibration isolation system are given respectively. Then, according to the force transmissibility, the vibration isolation performance is compared with conventional linear vibration isolator and quasi-zero stiffness vibration isolator. At the same time, the finite element analysis is carried out to verify the validity of the analytical solution. Finally, the influence law of the system parameters on the vibration isolation performance of the new type vibration isolator is analyzed and given. The results show that when compared with the conventional linear isolators, the new isolators have smaller dynamic stiffness and higher damping output, and when compared with the quasi-zero stiffness isolators, the new isolator not only can guarantee low stiffness and high damping output, but also has better stability and static bearing capacity. The design parameters of the vibration isolation system have a greater impact on the vibration isolation performance. Various design parameters of the vibration isolation system can be flexibly adjusted to meet different vibration isolation requirements.