Abstract: Aiming at the safety problem of high gas emission caused by double unloading in the mining process of 222 fully mechanized caving face of Xiashijie Coal Mine, which leads to excessive gas emission, combined with the theory of mining fissure “O” circle and “annular fissure body”, the analysis based on the failure characteristics of the overlying rock caused by double unloading in fully mechanized caving mining in thick coal seams, physical similarity simulation and FLAC3D numerical simulation are used to study the evolution model of overlying rock cracks in the goaf of double unloading working face, and the fissure field and the stress field evolution feedback mechanism, according to the crack density, divides the overlying rock fissure field into a permeable area, a longitudinal permeable area and a horizontal permeable area. Combining the Fluent simulation of the gas flow field migration mechanism, the double unloaded goaf overlying rock fissure field + stress field + gas seepage field are coupled with each other to further supplement the gas flow field law in the goaf: low-level low-concentration gas flow zone and high-level high concentration gas flow circle. The dual unloaded goaf gas control method is proposed, which is a high-position directional boreholegas drainage scheme in the compound goaf, and has been applied in engineering. The results show that the range of the compressed gas extraction and enrichment area is determined to be that: the width of the working face on the return side is 40 m, and the distance from the roof of the coal seam is 60.8 m to 150 m. Through the implementation of the high-position directional borehole gas drainage program in the compound goaf, the gas concentration in the upper corner is lower than 0.8%, and the gas concentration in the working face and return airway is lower than 0.3%.