The buried depth of - 817 inner water sump of the Wangfenggang coal in Huainan Mining Industry Group is about 850m. Though the surrounding rock had been repaired time after time, it was diffictdt to keep its stability. According to the effect of initial insitu stress field and the analysis of failure causes, a new repairing method for the water sump was developed, in which bottom counter arch and steel fiber reinforced shot - con- crete are used. The excavation damage zones in the deep surrounding rock of the water sump under different supporting patterns were simulated with a user - defined constitutive model of FLAC software. The results indicated that the excavation damage zones can be reduced by the new repairing support pattern. Test in field indicated that the new repairing support pattern is success which can maintain the stabilization of the surrounding rock.