Abstarct: Considering the importance of combustion of gases, which is an important issue in the field of production, transfer and exploitation of gases, it is very important to study and predict the flame behaviour and the conditions affecting it. Flame behaviour in a closed environment is more complicated than open combustion, so focusing on this process requires special attention. Under conditions, if a source of poor energy is sparked inside a pre-mixed gas mixture, the flame front is formed and the combustion process begins. As a result of the conditions, including the turbulence of the flow and the boundary conditions of the walls, the flame can slowly flame and finally become detonation, which is a very destructive and dangerous phenomenon. The process of propagation of the flame front inside the gas mixture depends on the type of flow and the chemical nature of the gas and the governing boundary conditions, which causes various instabilities in the flame front, and the velocity of the flame front depends heavily on this. According to the previous studies in the relevant section, the effect of the porous medium on the combustion flow and flame front, including pressure variations, burning rate and the structure of the flame front, have been studied. The present study is an experimental study of the propagation of the flame methane-air stoichiometric mixture in a closed duct and the effect of the porous medium on the structure of the flame front and the parameters affecting its propagation. The effects of porous obstacles in the flame growth path and flow field have been studied in a closed duct experimentally. The effect of porous obstacles with solid to its different heights has also been studied. To focus on the effects of the porous obstacle, a sample of solid obstacle selected from wood is also studied. The results reflect the fact that the amount of turbulence created in the flow field by porous obstacles increases the velocity of the flame propagation within the canal and generally maintains the initial positive flame acceleration relative to the state without a barrier, for longer periods and in some cases causes Increased flame acceleration also. Porous medium in the comparison with the solid medium has a special property that is visible in the results and it prevents the exacerbation of the compressive waves generated by the combustion process in the flow field. It is seen that they have been reinforced in the solid obstacle of compressive waves. Increasing the height of the porous obstacle has increased the turbulence in the flow field and changed the structure of the propagation of the flame front. In the case of pressure variations inside the enclosure, the presence of obstacles also had a significant effect, which reduced the maximum pressure inside the enclosure. Of course, it is noteworthy that porous obstacle had a lower impact on the maximum pressure produced inside the compartment than the solid obstacle. The change in the height of the porous obstacle is also generally developed with increasing height, the maximum pressure produced inside the close duct, in a shorter time.