Abstract: Due to the unique structure of isolated coal pillar，there are many problems in roadway driving among isolated coal pillar，such as high concentration of stress，low integrity of surrounding rock，and tough job in controlling the surrounding rocks.The model of the roadway driving along the gob is put forwards.Taking a mine as a case，the isolated coal pillar totally lies in the broken zone and plastic zone.There is no elastic zone for the pillar.Through PFC^2D partide flow code simulation，it is obtained that the whole pillar can be divided into failure zone and plastic zone.The range of failure zone on both sides of roadway is about 2.5 m.Anchorage zone needs to be beyond failure zone.Thus，rib cable is needed to control surrounding rock.The relationship between supporting resistance and fissure development is obtained.It suggests that compared with no support，a certain support can control the development of fissure effectively.Nevertheless，when support resistance reaches specific value，increasing support resistance has little effect on controlling fissure development.Through field monitoring and comparison of the surrounding rock deformations under the condition of different support patterns with support or not，it is obtained that layout of the rib cables at walls will significantly reduce the deformation rate of surrounding rocks by 10 mm/d to 15 mm/d，which can effectively control the deformation of surrounding rocks and make sure the normal service of roadway.

Key words: Isolated pillar, Plastic zone, Broken zone, PFC2D numerical simulation