Four contrastive experiments were carried out to study HMX re-crystallization morphology in propene carbonate solvent on different experimental conditions. Morphology of re-crystallization sample was obtained by optical microscope (OMS). OMS result show long-time crystallization can make crystal average particle size up to 2000 μm. Adding crystal seeds can avoid twin crystal and get uniform crystal morphology. Addition of crystal seeds and a little water makes morphology of crystal tend to be spherical. Morphology of crystal is more uniform if seeds exist. Crystal face of (100) always exists among the HMX crystal form from PC through simulution of the crystal structure. 