The ammonium perchlorate (AP) powder was coated and agglomerated to improve the powder propellant surface properties, which provided the conditions for Al/AP propellant long-term storage and high efficiency combustion. The energy characteristics of Al/AP powder rocket motor were calculated by Gibbs minimum free energy method, and the effects of the hydroxyl-terminated polybutadiene(HTPB) to AP powder on the loading density, hygroscopicity, and thermal decomposition were analyzed by pretreatment experiments. The ignition tests were conducted in the closed burner to study the effect laws of O/F and packing quality to the energy characteristic parameters of Al/AP powder propellant. The results show that, the optimal material ratio of AP pretreatment is 10%HTPB, and in this circumstance, the theoretical specific impulse of Al/AP powder rocket engine can be up to a maximum of 262.1 s at 3:1 of O/F. The energy characteristic parameters of powder propellant will increase with the growth of O/F in a certain rage; the gas generating quality of powder propellant per unit mass is basically equal at the same O/F, and both combustion temperature and velocity characteristics will increase with the growth of packing quality.