Abstract: Combined the engineering geology and production requirements of Shabatu Mine，the medium-hole pillar caving method with mining preparation out of veins and subsequent backfilling is proposed.To ensure the safe and efficient exploitation of the mine，ABAQUS simulation software is used to simulate the variation of roof displacement and stress when the stope span respectively at 15，20 and 25 m.The results show that the displacement at hanging wall is larger than that of footwall，and the internal displacement of the stope shows a uniform change as funnel-shaped curve and minimum at span of 20 m and 15 m.The maximum principal stress (compressive stress) of backfill body under three spans above are 0.67 MPa，0.69 MPa，and 1.04 MPa respectively，wherein the maximum principal stress at 25 m span have been close to or above its compressive strength.Considered for mining safety and efficiency，20 m span of stope mining determined as the best.The result provides reasonable scientific basis for the production of mine.By applying in Shabatu Mine，the mine has produced over one million tons of mines in safe and efficient way.It obtains production effect and achieves the desired purpose.

Key words: Stope structure, Parameter optimization, ABAQUS, Stope span