Abstract: Simplifying of the complex reaction mechanism is of importance to the numerical simulation of the combustion of BFG (blast furnace gas). The software CHEMKIN was used to solve a one-dimensional mathematical model of steady-state pre-mixing laminar combustion. By analyzing the effects of basic components of BFG on the combustion rate in all elementary reactions, the simplified reaction mechanism was obtained and becomes the basic mechanism of BFG combustion. Compared the computed result by the simplified mechanism with that by complex mechanism, the time required for the former was less than 1 s but that for the latter was about 18 s. The differences between molar fractions of the BFG components computed by the two mechanisms were less than 0.4%. The reliability of the simplified reaction mechanism is therefore verified.