In order to find a solution to the surplus tailings of Dongguashan Copper Mine and the treatment of the open pit of Xinqiao Pyrite Mine,the cemented filling in the open pit was considered by using the surplus tailings of Dongguashan Copper Mine.There are still some high-quality hanging-wall ores in the east of the open pit,and the challenge to safely extract the hanging-wall ores must be coordinated and solved at the same time of cemented filling in the open pit.Based on Flac3D software,the numerical model of coupling action between mining and cemented filling with hanging-wall ores in open pit is constructed,and then the stability of stope and open pit slope in the process of hanging-wall ores extraction is analyzed under different cemented filling height and reserved pillar thickness.The results show that when the cemented filling height of the open pit is 0 m,96 m and 192 m respectively,the minimum thickness of the lateral isolated pillar is 8 m,6 m and 6 m respectively,and after the cemented filling of the open pit,the stress of the overburden on the open pit platform increases,and the maximum tensile stress of the top isolated pillar increases under the condition of backfilling,but it does not affect the reserved thickness of the top isolated pillar (8 m).The cemented filling in the open pit effectively improves the stress field environment around the hanging-wall ores stope and reduces the reserved thickness of the lateral isolation pillars.It not only ensures the stability of the mining area,but also improves the safety of hanging-wall ores extraction.