In view of the large number of goafs and remaining pillars in the mining process of No. 2 coal seam in Hufeng Coal Industry, the mining industry in the double mining face was complex, with difficult control of surrounding rock, and the coal wall of the working face was large. The failure range of surrounding rock, stress distribution and horizontal displacement of coal face in goaf with different width of residual coal pillar and different span were analyzed by means of numerical simulation, so as to determine the reasonable mining height. It was considered that the mining height of the working face should not exceed 3.0 m, less than 2.5 m.