Hyperelasticity of rubber waterstop material in gates plays a decisive role in numerical analysis. The mechanical behaviour of a vulcanized rubber is studied in this paper by a uniaxial tensile test, biaxial tensile test and pure shear test. A set of nominal stress—strain curves for different strain rates is obtained. A systematic comparison and analysis in general rubber constitutive models is performed. In the case of complete experimental data or incomplete experimental data, corresponding optimal constitutive mode is given. By the finite element calculation of waterstop around bottom outlet, different stress-relaxation time is given by adopting different viscoelastic constitutive models. Compared with the real situation, burgers constitutive mode is recommended to use. The implications for design and production for waterstop in practice are substantial.