Abstract: In order to research the damping effect of CO₂ on gas explosion, the constant volume bomb model and numerical methods were used to simulate the goaf (confined space), which is from the perspective of chemical kinetics to study the mechanism. The result showed that: the delay time of gas explosion increased, explosive strength gradually weakened, the inhibition of disaster gas (NO) and free radicals in the chain reaction strengthened with the crushing of CO₂; at the same time, the sensitivity coefficient of key reaction step which promotes production and consumption of methane constantly reduced overall, but the reduction in generation of CH₄ was less than the reduction in consumption of CH₄.