Abstract: In view of the exploitation status of a large scale open-underground combined mining of copper mine，the synergistic theory was introduced into stability analysis of the underground stope，and the synergistic effect on the structure size of stope，pillar and backfill fake pillar are mainly considered.The original stope structures are optimized.In order to ensure the optimized mine stope stability in roadway excavation and stope mining process，the stability of drifting tunnel and mining stope was numerically simulated under three filling schemes.The results showed that：in different filling program，and for the ore-body remaining to be exploited，large roadway basically keeps stable.In stoping process，the stability of stope is associated with the stiffness of the backfill materials.The stope strain and displacement are ideal while combining the high and low stiffness of backfill.The cemented lumpy-rock at the bottom and the tailings cement at the upside are the preferred alternative.Foe the 9m belled stope structure scheme，and in the stoping process，the stability of stope roof is increased，meanwhile，the ore removal roadway is less deformed and keeps stable.The optimized stope structure parameters have obvious advantages.

Key words: Structural synergy, Stope structure, Stability, Parameter optimization, Numerical analysis