Abstract: ased on site investigation in the field and underground shafT and drift, combining with laboratory analysis, we study on the structure, lithology and hydraulic charactristics of F3 fracture zone and discuss the causes of sudden flooding of the mine debris flow during underground mining. Synthetic studies on the hydrogeological framework, hydrochemistry, water isotopes and hydrogeothermics help us to anticipate potential engineering problems in further mining and put forward plans for prevention.The main purpose of this paper is that we pay much attention to the combination of engineering analysis with analysis of groundwater flow systems. It is proved that this is a right way to deal with hydrogeological and engineering problems in the mine area. In this manner we can reveal the causes and mechanism of some hazards during mining work. This facilitates us to take effective measures for preventing and controlling the potential hazards.