The crystal morphologies of α-and β-HMX were predicted by using attachment energy （AE） and Bravais-Friedel-Donnary-Harker （BFDH） models. The important crystal surfaces are (020), (011), 10-2), (11-1), 100) for β-HMX and (040),(220) and (111) for α -HMX. The analyses of the crystal surface structures show that (100) and (111) are greatly polar, and (020),(011),(11-1) and (220) are polar, while (10-2) and (040) are non-polar. It can be predicted that (100) and (111) are the important crystal surfaces in the proton solvents with strong polarity,and the appearance area of (020),(011),(11-1) and (220) is increased,and the (10-2) and (040) surfaces diminishes or disappeares,while the contrary cases occurs in the non-polar solvents.