Ammonium perchlorate is one of the most important and applicable oxidizers used in solid propellants. Also, the morphology of ammonium perchlorate particles is an effective parameter in the production of propellants. In the current research, the preparation of ammonium perchlorate using the cooling crystallization method was studied. Four parameters including the rate of cooling, mixing patterns, agitator speed, and surfactant were considered in cooling crystallization of ammonium perchlorate. Nine tests were carried out based on the Taguchi experimental design method. The morphology of the obtained crystals was analyzed by optical microscope and MIP 4 student software. The size distribution of the particles was modeled using the Rosin‐Rammler method. Obtained results illustrated that the surfactant had the most effect with the value of 70.7 % and the agitator speed, flow pattern, and cooling rate had fewer effects on the morphology with the values of 25.8 %, 2.9 %, and 0.2 %, respectively. The optimal amount of sphericity obtained by the Taguchi method was 0.77 which was verified by the experimental result of 0.76. The roundness and aspect ratio values for the optimal crystal were 0.79 and 1.40 respectively. Applying the Rosin‐Rammler model showed that the homogeneity factor of size distribution was 2.22 for the optimal crystals.