The invention discloses a quasi-zero-stiffness vibration 
isolator with a horizontal 
damper. Two sets of 
cam-roller-spring mechanisms are horizontally and symmetrically arranged to serve as a negativestiffness structure, the horizontal 
damper is additionally arranged, and then the 
negative stiffness structure, the horizontal 
damper and a vertical positive stiffness spring structure are connected in parallel to form a quasi-zero-stiffness 
vibration isolation mechanism jointly. The matched stiffness coefficients of vertical springs and horizontal springs are selected, the height of cams and thepre-compression amount of the horizontal springs are adjusted according to the 
mass of an object subjected to 
vibration isolation and the stiffness of the vertical springs, the centers of the 
cam androllers are made horizontally flush, and the 
system has the quasi-zero-stiffness feature at the balanced position. On the basis of the certain vertical damping, the horizontal damping of the 
system isreasonably designed, and the 
resonance phenomenon of the 
system can be restrained or even eliminated. The vibration 
isolator has the high-static and low-movable stiffness feature, can achieve low-frequency 
vibration isolation, is simple in structure and convenient to maintain, and can be widely applied to low-frequency vibration management projects.