Abstract: For the complex situation of Tonglvshan No.1 orebody in underground mining transferring from open-pit，influence of fault in hanging rock was analyzed by FLAC^3D，in order to guide on-site construction.One model with fault and another model without fault were established respectively.Two models took the same form of excavation：stope 1 and stope 2，leaving column between two stopes in order to support the roofs.The results of excavation by both of methods are compared through stress and displacement，and the research indicates that the fault makes the situation of mining worse，mainly showing two aspects: ①fault weakens the integrity and continuity of hanging rock，and makes the compressive stress on stope-boundary increase by 0.01~0.45 MPa；②when the thickness of pillar is large，fault seldom influences stope 1，but makes large influence to stope 2，causing the increasing subsidence of the roof，and showing that the roof of stope 2 rotates around the top of the column.When the thickness of pillar h≤16 m，fault makes influence to both of stopes，leading to their roofs' displacement increase conspicuously，and showing that both of stopes' roofs rotate around the top of left-boundary in stope 1.

Key words: Mining engineering, Transferring underground mining from open-pit, FLAC^3D, Fault, Goaf