Abstract: To reduce the starting isolation frequency of the isolator， enhance adaptability to different vibration sources， and achieve superior vibration suppression effects compared to traditional passive isolators， this study proposes a high static-low dynamic stiffness （HSLDS） isolator with asymmetric stiffness structure employing electromagnetic coils nested with permanent magnets. It can adjust the system stiffness according to changes in vibration source frequency， thereby realizing semi-active vibration isolation. The incremental harmonic balance method is employed to obtain the displacement transmissibility characteristics of the system under different excitations and currents. Based on the system model of the isolator， a semi-active control strategy is proposed in this study， which can adjust the system stiffness according to changes in vibration source frequency. An experimental test platform was constructed for experimental research. The results show that the proposed HSLDS isolator can reduce the starting isolation frequency by 19.25%. Introducing the semi-active control strategy can attenuate the maximum acceleration amplitude by 54.7%.