Abstract: The western Shizishan deposit of Dongguashan Copper Mine，is a deposit that has been explored since 1960s last century.A group of extra-large mined-out spaces are formed in 2002 with the feature of large volume and wide distribution.These mined-out areas bring great safety risks for normal production.For this，combining with its own characteristics，and based on the related investigation and research，Dongguashan copper mine treat the mined-out areas with full-tailing filling method.In practice，taking the eastern Shizishan mined-out area as a testing site，the mined-out areas are treated step by step.Then he successful experiences are fully applied in the Western Shizishan Mined-out area，with good economic and social benefits achieved.

Key words: Underground mine, Extra-large mined-out area, Full-tailings filling