2, 4, 6-trinitrotoluene/2, 4, 6-trinitrochlorobenzene (TNT/TNCB) cocrystal explosive was prepared by cocrystallization in solution, and its crystal structure was characterized by single crystal X-ray. Results show that the crystal crystallizes is in monoclinic system, space groupP2₁/c with crystal parameters of a=2.1148(5) nm, b=0.60974(14) nm, c=1.4968(4) nm, α=90°, β=110.374(4)°, γ=90°, V=1.8093(7) nm³, Z=4. The thermal property and impact sensitivity of the product were measured by differential scanning calorimetry and sensitivity test, respectively. Results reveal that the melting point of TNT/TNCB cocrystal explosive is 72.7 ℃ and theH₅₀ of the cocrystal is 92.9 cm, which are lower than those of TNT and TNCB. Furthermore, the detonation velocity and pressure of TNT/TNCB cocrystal explosive were also calculated to be 7508 m·s^-1 and 24.52 GPa by density functional theory (DFT) and Kamlet-Jacobs equation.