Based on the air leakage condition of bedding plane in gob, combined with the mining example of NO.21208 working face of Huojitu mine in Daliuta colliery, the caving of roof rock strata of gob are divided into three zones, namely free caving zone, roof fracture zone and surface sandy sole zone. The mathematical model with finite solution for bedding plane air-leakage is established, in which the air leakage intensity is regarded as attenuating follows proximately negative exponential law. According to the solution of flow equation of air leakage motion by using finite element method, conclusions can be drawn that the pressure between the pressure chamber formed by gob caving zone and the surface causes the air leakage of gob bedding plane, the air leakage intensity varies little along the length direction of working face, and the air leakage intensity of gob bedding plane is determined by two factors, namely the size of the roof fracture zone and the thickness and compactness of the surface sandy soil zone.