The rebound formula of the viscoelastic damper at any time is received through the anlysis of mechanical properties of viscoelastic damper.Relative displacement formula of differ-rigidity viscoelastic brace is deduced by using the model of three-differ-rigidity available.As well as the braces are applied into the high-level steel structure system.The result of finite element of systerm with viscoelastic damper illustrate that the ability of dissipative energy is remarkable.