In this study, a new co-crystal explosive of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX)/1,3,5-triamino-2,4,6-trinitrobenzene (TATB) (molar ratio 1 : 1) was designed based on crystal engineering. The crystal structure was predicted using the polymorph predictor (PP) method. The main properties of co-crystal consisting of mechanical properties, stability, and interaction formats were simulated through molecular dynamics methods. Simulated results indicate that the crystal structure of the HMX/TATB co-crystal may belong to the P (1) over bar, P2(1)2(1)2(1) or P2(1)/c space group. The calculations of the binding energy and the analysis for radial distribution function show that the two components are connected through electrostatic hydrogen bonding and strong van der Waals interactions. The new co-crystal has better mechanical properties with the moduli systematically decreased. With the appearance of the new crystal, the trigger bond N-NO(2) has little change.