Abstract: In order to reduce the seismic response of structures,a sort of viscous damper is developed by using a silicon-based polymer material as the viscous medium which more energy can be expended when the damper works.The expressions of hysteresis loops and dynamic stiffness of the damper are also discussed.The evaluating criterion of energy dissipation capacity for designed damper is developed,and the calculational method of the parameter is given on the basis of experimentation.Some superior features are proved through the experiments on the damper,such as plump hysteresis loops,simple structure,no leakage of viscous medium, self-protection.