Ammonium perchlorate (AP)-based composite propellant has been widely used as a solid propellant, but higher burning rates are in demand. We report that crystal-habit-modified AP is an effective oxidizer that increases the burning rates of propellants. The modified APs have a dendritic shape. However, dendritic AP is not convenient to mix and cast in an AP/binder slurry because of its high viscosity. We attempted to prepare a crystal-habit-modified AP with polygon or sphere form. The crystal habit of AP was modified by ethylene glycol such that the intensity of the lattice plane (210) of the modified AP was remarkably high. The shape was almost hexahedral, and the mean particle diameter was approximately 150 mu m. (C) 2010 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.