Abstract: The three-parameters rheology equation of viscoelasticity of rubber waterstop material is formulated by use of constitutive model of differential coefficient. Combining with the test of viscoelasticity of waterstop material, the influence of the waterstop effect of the viscoelasticity of waterstop material is analyzed when the flood peak is high. By means of principle of stress relaxation function of material, effectual waterstop time of three kinds of waterstop material is obtained theoretically. The equation is significant for viscoelasticity research of rubber waterstop material, and it can offer useful reference for pertinent practical engineering.