Abstract: For the characteristics of slowly-inclined，broken，medium thickness ore-body，the sublevel room-pillar mining method is put forwards to exploit the mineral resources.In the test stope，the surrounding rock has a better stability，but the hanging wall boundary of the ore body lies in broken alteration zone with broken rocks.The surface water in the mine is developed well，and there is s aquifer layer at hanging wall of the surrounding rock.The caving of the surrounding rock produces a great impact on the ore dilution and the safety mining.The hanging pillars are reserved to slow down the surrounding rock caving.The FLAC3D is used to make numerical analysis on the stope stress migration，displacement and the destruction rule per unit.The results showed that the reserved 2 m pillars are beneficial to maintain the stability of the hanging wall，control the extending of plastic zone，so as to lower the ore dilution and achieve the safe mining.

Key words: Slowly inclined broken orebody, Method of piecewise chamber, Reserved pillar, Stability of surrounding rock