The author makes an approach to several kinds of methods which the exis-tent mill tailing were used fully to fill the underground mined-out area. Compared with the filling methods used currently in Dachang mine, they not only can reduce the filling cost greatly and increase doubly a capacity of filling , hut also can make the abandoned tailing reservior to be reused, eliminate a large investment in the construction of new tailing re-servior, prevent the pollution of tailings and bring about a great advance in good cycle of mining and mineral processing as well as result in a great economic and social benefits.