Precision instrument will be disturbed by the vibration of mechanical equipment in the working process, which will deteriorate its normal operation and delay the test progress. So, it needs to be protected by vibration isolation device. In this paper, a hybrid vibration isolation platform is proposed which contains a high static low dynamic quasi-zero stiffness isolation system and a passive bilayer isolation system. And a fully flexible impedance dynamic model is established for this system based on the impedance synthesis method. The vibration transfer characteristics of the hybrid platform under the real excitation of the engine testbed are analyzed and verified by relevant tests. Results show that the designed vibration isolation device has fine broadband vibration isolation effect and can meet the usage requirements.