Abstract: For the unstable ore rock conditions of much broken ores in local underground mine，and in order to ensure the safety of mining roof，the small drift slicing cut and fill stoping is adopted，and the mining height and width is generally controlled at 4 m.Due to its mall section size of the room and low efficiency in rock blasting，this stoping method seriously restricted the production capacity.In order to explore a more safe and efficient mining method，and ensure the safety of roof rock，attempts a lot by referring to the downward blasting method in open-pit mine and the high precision hole-by-hole blasting technique.Then，the downward medium-height hole-by-hoe denotation process with pre-control roof for underground mine is proposed and cumulated in success.Due to large scale support on stope roof and sidewalls before blasting，this process can ensure the follow-up working procedure and personnel security.As the stope section size increases，the blasting efficiency increases，and the capacity of single room improves significantly.At the same time，the downward medium height drilling makes the efficiency increased，the labor intensity of workers reduced，and the working environment improved obviously.

Key words: Pre-control roof support, Hole-by-hole detonation, Downward medium-depth hole, Reduce blasting vibration, Increase production capacity