The effects of aluminum particle size on agglomeration situation orburning rate of aluminum powder were investigated.The experimental results and theoritical analysis indicate that the increase of aluminum particle size obviously decreases its agglomeration, but fine-grained aluminum improves its ignition and combustion characteristics.Due to the influence of aluminum particle size on thermal effect of the propellant burning surface, the burning rate decreases with the increase of aluminum particle size in low burning rate propellant,but the situation is opposite to that in high burning rate propellant.Therefore,reasonable use of aluminum particle size is very important to formulation design of solid propellants.