Abstract: In order to recover the ore pillars in mined-out area，and taking filling body of mined-out area in Daye Iron Mine as a case，the stress analysis model of the mined-out area is built，based on Mohr-Coulomb material deformation model.The stress variation and the distribution of plastic zone in the mined-out area before and after filling are simulated to obtain the stability of the mined-out area through the contrast.The study shows that filling the mined-out area can not only improve stress action in the mined-out area，but also shorten its plastic zone.To a large extent，backfilling improves the stoping stability of the mined-out area.

Key words: Stability of mined-out area, Filling, Mohr-Coulomb model, Numerical analysis