Abstract: To deal with the problems of small time step and low computational efficiency caused by the rigidity of the chemical reaction in the flame acceleration and deflagration-to-detonation numerical simulation, a general simplified method for the gas fuel explosion chemical reaction model was proposed. The Arrhenius parameters optimization design method of simplified reaction model based on genetic algorithm was established, so that the simplified reaction can obtain flame characteristic parameters similar to the detailed reaction mechanism and the maximum error is no more than 5%. On this basis, coupling the simplified reaction model with the multi-component reactive fluid Navier-Stokes equation, the large eddy simulation method was used to conduct the efficient and accurate simulation of the gas fuel explosion chemical reaction process. The proposed method is verified by the simulation of the hydrogen explosion process in an open space. The simulation and experimental comparison results show that the method proposed in this paper can approximate the actual physical process with high efficiency and accuracy, and make up for the low efficiency of detailed reaction mechanism simulation. It also has good adaptability to the chemical reaction process of various gas explosions.