Abstract: In the southeast mining area of Gongchangling Iron Mine, the open-pit mining is applied to mine the upper iron-bearing belts, and the sublevel caving method without sill pillar is used to mine the lower iron-bearing belts.The height of the parallel ore between the upper and lower iron-bearing belts is about 300 m because of the unreasonable mining planning, which seriously affects the safety of mine production.To ensure the safe production of open-pit and underground in the mine, it is proposed to fill the collapsed pit in the lower iron-bearing belts with waste rock stripped from the upper iron-bearing belts.FLAC^3D software is used to simulate the mining process of the iron-bearing belts, and the law and range of the surface rock movement under the action of with and without fillings is compared and analyzed.The results show that the strata movement contour is near the surface of the vertical broken line with the increase of mining depth when there is no filling material in the collapsed pit.When the mining level of the lower iron-bearing belt is below 110 m, the hanging wall of the collapse pit is easy to appear dangerous deformation.When the mining level of the lower iron-bearing belt is 70 m, the horizontal displacement and subsidence of the ground surface decrease with the increase of the filling height.Meanwhile, the effect on controlling horizontal deformation is more significant than controlling tilting deformation.The height of the granular rock in the collapsed pit needs to be kept at 160 m to avoid dangerous deformation of rock mass in the open-pit.For the sake of safety, the ultimate mining level of the lower iron-bearing belt is finally determined to be 110 m.The monitoring results of surface rock movement show that the method of waste rock to fill the collapsed pit can ensure the coordinated and safe production of the upper and lower iron-bearing belts in the southeast mining area of the Gongchangling Iron Mine when mining the iron-bearing zone above the level of 110 m.