In order to analyze the effect of different combinations of stretching rates of hydroxyl-terminated polybutadiene binder (HTPB) propellants on the accuracy of the parallel rheological framework model, a nonlinear viscoelastic constitutive model of the propellants was developed based on the parallel rheological framework method. Combined calibration of the constitutive model for different tensile rates, the corresponding constitutive model parameters were obtained and compared with experimental results using finite element models and numerical calculations. The constitutive model errors of the calibration for different rate groups were compared and analyzed. The results showed that the model can be calibrated more accurately when a combination of high rate and low rate groups was used, without the need for extensive experiments at intermediate rates. And the high rate propellant tensile test rate could be up to 3000 mm/min, no need to increase the rate. This analysis gave justified suggestions for simplifying propellant material tests and improving the efficiency of the experiments. Provided a method for rapidly predicting the mechanical properties of propellant materials.