Abstract: In order to study the influence of the porosity of blocking air-leakage material on the O₂, CH₄ gas migration and the coupling disaster of coal spontaneous combustion and gas in the goaf of working face Y-type ventilation cutting roof and retaining roadway, taking the goaf of 110 working method working face of Dalong Mine as the object, based on Fluent simulation software, a simulation model for the influence of the porosity of blocking air-leakage material on the gas migration in the goaf was constructed. The simulation study was conducted on six kinds of porosity (0, 0.1, 0.2, 0.3, 0.5, 1.0) corresponding to four commonly used blocking air-leakage materials and two extreme ideal conditions of complete blocking air-leakage and complete open without blocking air-leakage in the goaf of the working face with cutting roof and retaining roadway. The research results show that the porosity of blocking air-leakage material for the cutting roof and retaining roadway has a great influence on the O₂ volume fraction distribution in the goaf. With the increase of the porosity, the position and range of the scattered zone and the spontaneous combustion zone in the goaf move back and expand. The width of the spontaneous combustion zone on the side of the main air inlet roadway and the side of the cutting roof and retaining roadway increases from 12 meters and 22 meters when the porosity is 0 to 19 meters and 60 meters when the porosity is 1.0. The range on both sides of the spontaneous combustion zone increases by 58.3% and 172.7% respectively, the spontaneous combustion zone with narrow strip distribution and expanding range appeared on the roadway side of the working face. The high concentration gas accumulation area moves to the deep part of the goaf and the accumulation area decreases continuously. The accumulation starting position moves from 100 meters lagged working face to 150 meters lagged working face. With the increase of porosity, the area of coupled disaster of coal spontaneous combustion and gas is constantly expanding. Compared with the three methods of blocking air-leakage by spraying polyurethane foam, using modified cement mortars, cement mortars and filling with gangue, the area of coal spontaneous combustion and gas coupling disaster in goaf is significantly reduced, which is more conducive to the management of coal spontaneous combustion and gas coupling disasters in goaf.