To investigate the quasi-static tensile mechanical properties of aging high solid content modified double-base propellants （CMDB）， the uniaxial tensile tests of CMDB propellant were carried out at four different temperatures （323， 293， 273， 253 K） and different strain rates （3.3×10^-5， 3.3×10^-4， 3.3×10^-3， 3.3×10^-2 s^-1）. The CMDB propellant samples with different aging time （0，10，20，35，50，65，80，100 d） were tested by gas chromatography. The mechanical properties of CMDB propellant and the change of stabilizer content after aging were studied. The results show that the maximum elongation and the content of stabilizer decrease significantly during the aging process， which can be used as the failure criterion of the aging CMDB propellant. By using the time-temperature superposition principle （TTSP）， the maximum tensile strength curve of CMDB propellant was obtained， and the aging strength main curve equation was established， which could be used to predict the maximum tensile strength of CMDB propellant with different aging time in the range of quasi-static strain rate.