A composite solid propellant/liner microscopic finite element model was established based on the microscopic morphology and particle distribution obtained by SEM (scanning electron microscope). Using Cohesive unit to simulate the composite solid propellant matrix/particle interface and composite solid propellant/liner interface debonding. The effects of different particle content and strengthening/aging degree on the debonding process of composite solid propellant/liner interface under uniaxial quasi-static tension were calculated and analyzed. The results show that the aged of the liner interface and the increase of the number of particles will lead to the debonding failure of the liner interface. The failure strain increases with the increase of the particle content at the propellant/liner interface, while the peak stress decreases first and then increases.The peak stress and failure strain decrease with the aging of liner, but they are not sensitive to the strengthening of liner interface.