Seven kinds of models of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) /1,1-diamino-2,2-dinitroethylene (FOX-7) co-crystals were constructed based on the hydrogen bond rules of co-crystal formation. The probability of CL-20/FOX-7 co-crystal formation was investigated using the molecular dynamics (MD) simulation. The radical distribution function (RDF) was used to study the acting force between the molecules in co-crystal model. X-ray powder diffraction (XRD) was used to simulate and analyze the difference between XRD peaks of co-crystal models and pure components. The results show that there are strong hydrogen bonds and Van Der Waals forces between CL-20 and FOX-7.The binding energies of seven kinds of co-crystal models decrease in the order of E_b (1 0 1)＞E_b (1 1 -1)＞E_b (randomness surface)＞E_b (0 1 1)＞Eb (0 0 2)＞E_b (1 1 0)＞E_b (1 0 -1).The intermolecular forces of seven kinds of co-crystal models are stronger when some CL-20 molecules are substituted by FOX-7 on the surface (1 0 1) and (1 1 -1) . The XRD peaks of seven kinds of co-crystal models are quite different from that of pure component CL-20 or FOX-7. Therefore, it can be predicted that CL-20 molecule is more easily substituted by FOX-7 on the surface (1 0 1) to obtain the stable co-crystal structure in the preparation process of the CL-20/FOX-7 co-crystal.