Applying polymer theory, exploring study on theoretical estimatecalculating tensile intensity of dissolutionaddingplasticity propellant is put up from the side of chemical bond and intermolecular force. Selecting singlebase(SB),doublebase(DB) and TEGDN propellant,theoritalcalculation method of tensile intensity of dissolutionaddingplasticity propellant was studied deeply. Tensile intensities of propellant were tested in the meantime,and compared with theoretical estimatecalculation. It shows that theorital tensile intensity of SB,DB and TEGDN were calculated to be 3.8×10⁷ N·m^-2,11.2×10⁶ N·m^-2 and 10.1×10⁶ N·m^-2,respectively. Their testing values were 3.1×10⁷ N·m^-2,10.6×10⁶ N·m^-2 and 8.9×10⁶ N·m^-2,respectively. It can be concluded that tensile intensity of propellant is mainly provided by intermolecular Van der Waals force. Tensile intensity of dissolutionaddingplasticity propellant can be calculated theoretically by polymer theory.