A BAMO-AMMO alternative block (BAAB)-based thermoplastic composite propellant with 80% solid content was prepared using BAAB energetic thermoplastic elastomer (ETPE) as the binder, and the formulation was optimized through energy calculation. The densities, heats of explosion, glass-transition temperatures, and mechanical properties of the samples were determined by surface tension measurements, oxygen bomb calorimetry, differential scanning calorimetry and static tensile tests, respectively. The results showed that this composite propellant can reach a standard theoretical specific impulse of 275.45s (10MPa), a density of 1.8102gcm(-3), a heat of explosion of 6256kJkg(-1), a T-g of -50.46 degrees C, a tensile strength of 1.56MPa and an elongation at break of 20%, thus presenting a superior comprehensive property to BAMO-AMMO random block (BARB)-based thermoplastic composite propellant.