The utility model discloses a liquid viscoelastic damper which comprises a damping mechanism composed of a piston, a piston rod, an end cover, a cylinder and a liquid damping medium. An elastic mechanism which can provide rigid support for movement of the piston rod is connected to the damping mechanism. A connecting mechanism connected with an external building structure is arranged on the elastic mechanism. According to the liquid viscoelastic damper, rigid support is provided by elastic force generated by compressing and stretching the elastic mechanism, and repeated vibration is avoided under the small-load situation; due to the fact that the limiting function is added, excessive displacement in static loads is restrained; the liquid viscoelastic damper has the automatic reset function. In addition, the damping mechanism and the elastic mechanism are connected in parallel and are independent from each other; when structural damping calculation is carried out, adding calculation can be directly carried out, and use is easy and convenient. According to the liquid viscoelastic damper, the damping energy dissipation function is reserved, meanwhile, a plurality of defects of a solid viscoelastic damper are overcome, and the liquid viscoelastic damper is suitable for popularization in engineering of long-span bridges, high-rise buildings and the like, and particularly applicable to constructional engineering with the severe external environmental condition.