Abstract: With the deep coal mining in China, the contradiction between the mine water inrush from aquifer underling the coal seam and the decline ecological water level is more and more serious.Based on the analysis of the assemblage characteristics between the No.5 coal seam and the aquifer (auifuge) in Chenghe mining area, the present study is to investigate the depth of destroyed floor by combining the theoretical calculation and in-situ measurement.The influence of coal seam mining on the confined water underling the coal seam has been studied from the perspective of aquifer structure, ecological water level and water quality.The results indicate that the maximum depth of destroyed floor of the No.5 coal seam is 8-10.8 m, and the main control factors of the depth of destroyed floor are the dip length of working face and the lithologic association of floor. And there is a positive correlation between the dip length of working faceand the depth of destroyed floor, a negative correlation between lithologic association of floor and the depth of destroyed floor.Influence degree of the aquifer structure from large to small can be divided into Ⅰ, Ⅱ, Ⅲ level area, and the Ⅰlevel areas are mainly distributed in the central-south and north, which covers an area of 6. 78 km², accounting for 45. 2% of the total area; there is no obvious effect on water level and water quality.The paper puts forward a grouting reinforcement technology to protect water resources and stabilize the ecological water level in mining, and finds an effective way for the healthy development of coal industry in Weibei region.