Abstract: Aiming at the need of groundwater protection in a coal mine, a point-pillar back-filling mining technology with wide coal pillar and narrow strip is proposed. In order to successfully realize the strip water retaining coal seam mining, the retention of coal pillar during strip mining is analyzed. After analyzing back-filling methods, combined with the source of back-filling materials of the mine, the paste back-filling technology and process of the mine are put forward, the top connection rate of the back-filling effect evaluation index is analyzed, and the point-pillar back-filling is proposed to enhance the support effect. The single wing long wall method is adopted to arrange the back-filling and mining double working faces in the mining block, and total pressure ventilation system is formed. In the working face, different numbers of wide coal pillars are divided parallel to the cut-off direction, and each coal pillar can be mined with different rounds of narrow strips for mining. After strip mining, the roadway along the goaf shall be retained, the goaf （narrow strip after the stoping） is processed by the alternate method of point-pillar back-filling and complete back-filling. The roof is managed by point-pillar back-filling in the first round and the second round, and all back-filling in the third round and the fourth round. The numerical simulation analysis is used to predict and analyze the maximum surface subsidence after back-filling, the maximum surface subsidence occurs in the middle of the mining area, and its maximum subsidence is 106 mm, which is consistent with the monitoring data of on-site surface subsidence and theoretical calculation results. The research results have been applied in the coal mine site to realize the protective mining of groundwater resources, improve the resource recovery rate, reduce the back-filling cost and reduce the surface settlement.