Abstract：The key to realize water retention during mining is to determine the reasonable working face¢s advancing distance and the reasonable coal pillar size in shallow coal seam；and the reasonable face¢s advancing distance resulting from simulation material experiment has been proved by the practice. The numerical simulation is designed on the basis of the water fluid crack¢s height in rock according to different face¢s advancing distances resulted from simulation material experiment. The stress and strain dimension distribution are calculated by the computer program “ALGOR”；and two kinds of faces have been simulated as following：(1) the rock thickness of less than 30 m and the soil layer of lower than 20 m；and (2) the rock thickness of more than 30 m and the soil layer of more than 20 m. According to the Von Mises stress distribution，the greatest tensile stress distribution on sinking belt and the greatest sinking distribution on sinking belt，the coal pillar and overturning rock¢s stability are judged and the reasonable face¢s advancing distance is drawn. It is significant to realize the water retention during mining in the geological condition of Shaanxi Province and the prevention of desertification in mining area.
