AbstractViscoelastic (VE) dampers are one of the most promising techniques for reducing vibration in engineering structures caused by earthquakes and wind. This work aims to develop a kind of high-dissipation VE damper for civil structures at low frequency and large amplitude in shear mode. First, nitrile rubber (NBR)/organic small-molecule composite VE materials are optimized and then made into VE damper. In order to test the mechanical performance and energy dissipation performance of the VE damper, the dynamic mechanical performance experiments at different temperatures, frequencies, and amplitudes were implemented. The experimental results show that the VE damper exhibits great stiffness and excellent energy dissipation capacity under different loading conditions. Second, a fractional derivative model based on Gauss microchain, Williams–Landel–Ferry (WLF) equation, and internal variable theory is proposed to accurately describe the effects of temperature, frequency, and amplitude on the dynamic mechanical properties of VE dampers. Finally, the accuracy of the mathematical model of VE damper is verified by comparing the calculated results with the experimental results. The study provides a theoretical basis for effective vibration reduction of civil structures with VE dampers at low frequency.