In order to understand the phenomenon and mechanism of thermal ignition and hot spots growth in energetic materials, spatiotemporal behaviors of thermal shock propagation in CL-20/TNT co-crystal and initial chemical reaction process were studied by first principles based ReaxFF reactive force field molecular dynamics simulations. Thermal shock mechanical wave induced by continuous fast heating of two ends in energetic materials and keeping it at high temperatures combining NVT ensemble and Berendsen temperature coupling method. In addition, two kinds of high temperature conditions (3000, 4000 K) were set up to study the influence of temperature difference on the initial thermal decomposition rate. When thermal loading is 4000 K, particle instantaneous translation rate can reach 0.5 km·s^-1 in early thermal shock propagation process, higher than the situation of 3000 K. At the same time, high temperature will lead co-crystal energetic materials decomposition. Here, molecule recognition algorithm is used to analyze the initial products and species. The decomposition rate of CL-20 is higher than that of TNT in the thermal shock propagation process under two kinds of thermal loading. The higher temperature of the thermal loading, the less time required to completely decompose. Product identification analysis shows that the main products of CL-20/TNT thermal decomposition are NO₂, NO, H₂O, N₂, CO, CO₂, HONO, H₂O₂, CHON, H₂N, CH₂O, where, NO₂ is the early initial thermal decomposition product, N₂, CO₂ and H₂O are the final products.