Abstract: In Dongguashan copper mine，the large diameter deep hole mining method with subsequent backfilling is adopted，and many stopes are working at the same time，and gob is filled with the full tailings cementing once. Then，the numerical calculation software is used to simulate the three kinds of stope structural parameters to analyze the stope stability. The calculation results show that the longer the stope length and width are，the larger the maximum principal stress inside the surrounding rock is. When the stope width is 14 m，the length is 28 m，and permanent pillar thickness is 4 m，the stope plastic area is minimum，which is determined as the final stope structural parameter of the barrier pillar to realize its safe and efficient mining.

Key words: Numerical simulation, Barrier pillar, Mining method, Stability analysis, Stope structural parameter