To enhance practical values and improve safety and mechanical properties of 2, 4, 6, 8, 10, 12-hexanitrohexaazaisowurtzitane /1, 3-dinitrobenzene (CL-20/DNB) cocrystal explosive, two polymer binders, hydroxyl-terminated polybutadiene (HTPB) and polyethylene glycol (PEG), were respectively added along its crystalline surface (0 0 1) and the models of two kinds of CL-20/DNB cocrystal based polymer-bonded explosives (PBXs), CL-20/DNB/HTPB and CL-20/DNB/PEG were constructed. Under the COMPASS force field, the 295 K-NPT molecular dynamics simulation (MD) study for cocrystal explosive and two kinds of PBXs models was conducted. The interface interaction between binder and explosives was explored using the pair correlation function (g(r)). Results show that the binding energy of CL-20/DNB/PEG is larger than that of CL-20/DNB/HTPB, predicting that the stability and compatibility of former is better than those of latter. In comparison with CL-20/DNB cocrystal explosive, adding of small amount of binder (HTPB or PEG) makes the elastic constants (C_ij), tensile modulus (E), bulk (K) and shear (G) modulus decrease, while Cauchy pressure (C₁₂-C₄₄) and K/G value increase, showing that the stiffness of the PBXs system is weaker, and its ductibility is better. The values of (C₁₂-C₄₄) and K/G of CL-20/DNB/HTPB system are larger than those of PBX CL-20/DNB/PEG, indicating that the ductibility of former is better that of latter, predicting that the desensitizing effect of HTPB by improving the cocrystal explosive's mechanical properties is better than that of PEG.