Through an analysis and investigation on the fragment size and flow characteristic of the waste overburden at the open-pit bottom of Deep Copper Mine,it was determined that a scheme of using cemented tailings fill after the first step mining(10 m span) of ore block and then directly utilizing the above waste overburden for filling after the second step mining (20 m span) should be adopted.This scheme is difficuilt in technology but its economic result is obvious so that it can be used for reference to the mines turning from open-pit mining into underground mining.