Abstract: In order to solve the problem of roof fall and frame pressing when the fully mechanized top coal caving face passes through parallel and oblique goafs, taking the goaf group of coal pillar recovery in Zhangcun Coal Mine as the research object, FLAC3D is used to optimize the column spacing of the goaf supported by flame-retardant PVC concrete column, and the distribution characteristics of stress, displacement and plastic zone of the surrounding rock of the goaf are analyzed. The results show that considering the factors of safety, cost and construction, the flame retardant PVC concrete column spacing of 2 m is relatively better; With the continuous advancement of the working face to the roadway, the approach amount of the roof and floor increases first and then tends to be stable; The vertical stress of surrounding rock increases first and then decreases as a whole. After the support of flame retardant PVC concrete column, the plastic area of surrounding rock of empty roadway is significantly reduced, and the plastic area is mainly distributed at the top of roadway and near the working face; At the same time, the surrounding rock stress is transferred to the flame retardant PVC concrete column, and the approach amount of the top and bottom plate is significantly reduced, with the maximum value of 129 mm, which is 70% lower than that before support.