A novel CL-20/TNT cocrystal explosive was prepared by cocrystallization in solution, and its morphology was characterized by scaning electron microscopy (SEM), and the crystal structure was determined using single crystal X-ray. Results show that the crystal is orthorhombic, space group Pbca with crystal parameters of a=0.9735(2) nm, b=1.9912(6) nm, c=2.4695(6) nm, α=β=γ=90°, V=4.787 nm³, Z=8. The thermal decomposition and impact sensitivity of the product were measured by differential scanning calorimetry (DSC) and sensitivity test, respectively. The results reveal that the exothermic decomposition of CL-20/TNT cocrystal explosive occurs in the temperature range of 180-275 ℃, and the melting point of TNT significantly increases by about 50 ℃. CL-20/TNT cocrystal has lower impact sensitivity and the impact sensitivity of CL-20 obviously reduces by 87%.