Supercritical fluid processes have gained great attention as a new and environmentally benign method of preparing the microparticles of energetic materials like explosives and propellants. In this work, HMX (cyclotetramethylenetetranitramine) was selected as a target explosive. The microparticle formation of HMX using supercritical antisolvent (SAS) recrystallization process was performed and the effect of organic solvent on the size and morphology of prepared particles was observed. The organic solvents used in this work were dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), cyclohexanone, acetone, and N-methyl pyrrolidone (NMP).