This study elucidates the kinematic viscosity, calorific value, and flash point of three biodiesel-diesel fuel blends. New prediction equations for the calorific value was established based on the kinematic viscosity and flash point respectively, and an optimal mixing ratio of the biodiesel-diesel fuel blends was obtained. Based on the mixing ratio, it was found that the Lederer equation, theoretical calorific values calculated using mass fractions, and the Hu-Burns equation are effective in predicting the kinematic viscosity, calorific value, and flash point of the three biodiesel-diesel blends . The power exponent model was found to be most suitable for elucidating the relationship between kinematic viscosity and calorific value. The exponential decay model was most suitable for exhibiting the relationship between the flash point and calorific value. The MAPEs are 0.16%, 0.39%, and 0.38% with kinematic viscosity, and 0.51%, 0.25% and 0.30% with flash point. Therefore, the calorific values obtained using these two models exhibited high accuracies. Taking kinematic viscosity, flash point, and calorific value as the optimization indexes, the optimization interval was determined, and the best biodiesel mass fraction mixing ratios were determined to be 24.37%, 25.06%, and 25.24%