In this paper, the characteristics of energy-absorbing capacities of the viscoelastic damper and its applications to the seismic mitigation of structures during earthquakes are studied. An innovative analytical model for the viscoelastic damper accounting for the earthquake-like and wind-like loadings and temperature effects, in good agreement with experimental results, and finite element formulations for the viscoelastic damper are presented. The applications of proposed methodology to a structure incorporating viscoelastic dampers is examined while subjected to horizontal and vertical earthquake ground motions. Numerical results show that the responses of the structure equipped with added dampers to earthquake loadings are significantly reduced. The same concept can also be applied to many types of structures for vibration reductions.