Abstract: Chenchao iron mine expects to stope the ore above -500 m using the method of recycling safety pillars under dressing-plant by filling method as continuing to use pillarless sublevel caving to stope other bodies in the similar stage.The similar simulation model experiment is carried out to explore the influence of methods above on the surface of dressing-plant area.The experimental results show that underground mining activities have a bigger influence on surface between the range of 20 m and 150m from the collapse pit edge，and almost have no impact on the distance more than 150m.The situation of surface subsidence of dressing-plant area and the general rules between the strain of subsurface rock and the distance to collapse pit edge were obtained.So，it is feasible for making the dressing-plant protection and stoping the ore above -500 m by the method mentioned above.

Key words: Backfilling, Caving, Surface deformation, Similar simulation model experiment