Abstract: In order to determine the surface air leakage range of shallow thick coal seam mining, based on the technical conditions of 6104 working face in Chuancao Gedan Coal Mine, the distribution law of overburden mining fracture and gas leakage fissure in shallow thick coal seam mining were studied by means of field measurement, numerical calculation and theoretical analysis. The results show that the overburden mining fractures in shallow and thick coal seam mining can be divided into permanent fracture zones on the side of workface starting line, as well as the fissure initiation zone, the fissure propagation zone and the fissure closure zone distributed dynamically with the working face mining; the fissure propagation zone in 6104 working face is 0 m to 100 m behind the working face. Field measurement shows that the gas leakage fissure zone in 6104 working face is 0 m to 80 m behind the workface, and the gas conductivity decreases with the increase of the distance from crack to working face.