We performed ab initio molecular dynamics simulations to study interaction mechanisms of binary mixture systems of explosion products (H2O, CO2, and N-2) under high temperatures and pressures. It is found that there is no reactions in the CO2-N-2 system at extreme conditions. Only at 4000 K and 50 GPa, the mixture of H2O and N-2 began to decompose. The H2O and CO2 mixture can readily react and ultimately form different reaction products even at a relatively low temperature and pressure in contrast with the above two mixtures. The temperature plays a negative effect on the interaction in the H2O-CO2 system.