Abstract: Taking the abandoned open mining pit of a copper mine as an example，the geological survey，mining conditions，formation reasons and basic conditions of the abandoned open mining pit of the copper mine are expounded. Combined with the actual situation of the open mining pit，the backfilling test scheme of the open mining pit is formulated. The research showed that after taking some measures such as leveling the bottom of open pit，seepage prevention，underground sealing，construction of drainage system，inspection and monitoring，the tailings are successfully backfilled. On the one hand，it solves the shortage of reclamation materials for the open-pit backfilling. At the same time，it also consumes the tailings produced by the concentrator，reduces the surface stacking of tailings，avoids the construction of tailings ponds，saves the mine investment and land resources，which is of important practical and environmental significance for the efficient mining and development of mines，and provides a new idea for the similar open-pit mining and tailings disposal in the future.

Key words: open mining pit, backfill, tailings, tailing pond