The effect of spherical and non-spherical aluminum powder on the combustion behavior of the low burning-rate HTPB propellant was studied by means of both static burning-rate measurement and firing test of the>112 mm evaluation test motor. The results showed that the burning-rate of the spherical aluminum propellant could be adjusted by means of variation of the particle size combination of the oxidizer. The results also showed that the burning-rate at high pressure and the burning-rate exponent of the spherical aluminum propellant are higher than those of the non-spherical aluminum propellant. There is no remarkable change in temperature sensitive coefficient of burning rate.