Because the precision instrument is more sensitive to low frequency vibration, higher requirements are put forward for vibration control, and quasi-zero-stiffness isolator with semi-active control is proposed. Firstly, the basic structure of quasi-zero-stiffness is introduced, and the static characteristics of the quasi-zero-stiffness isolator are derived. Secondly, the dynamic characteristics of the quasi-zero-stiffness isolator are analyzed, including the relative displacement transfer rate and the displacement transfer rate of the vibration isolator under the basic excitation conditions, and the influence of the damping characteristics on the dynamic characteristics is analyzed emphatically. Finally, a semi-active damping control strategy is established to further control the vibration. The results show that zero-stiffness isolator has a low initial frequency, and the vibration isolation band width, and semi-active damping control can eliminate resonance, and maintain the vibration control properties of non-resonant frequencies.