In order to explore the effect of bonding agents on the mechanical properties and chemical ageing resistance of hydroxyl-terminated polybutadiene (HTPB) solid propellant, molecular dynamics method and COMPASS force field were adopted to simulate the adsorption energy and mechanical properties of the interfaces constructed by HTPB, bonding agents and crystal faces of Al and Al/Al₂O₃. Then simulations were applied to estimate the diffusion coefficients of H₂O and O₂ in different bonding agents membranes. The results show that bonding agents increases the interaction of solid grain and HTPB, and improves elastic modul of Al/HTPB layer showing the enhancement of HTPB system rigidity. The trend of ability of restraining the diffusion of gas is consistent with experimental chemical ageing resistance of different bonding agents.