We report the most stable packings of five HMX/solvent supramolecular assemblies. A series of 1 : 1 supramolecular synthons of both α-form and β-form HMX conformers with solvent molecules were investigated. Both α-form and β-form HMX conformers have similar stability when combining with solvent molecules into supramolecular synthons. AIM analysis was performed to evaluate the properties of the intermolecular hydrogen bonds between the HMX and solvent molecules. The most stable polymorphs among the 10 most common space groups for α-HMX/solvent supramolecular assemblies were predicted and compared with available experimental data.