Abstract: Taking instance data of height of water flowing fractured zone from different mining area as analysis samples,the influential factors about geological structure conditions,mechanical strength of rock and excavation disturbance have been analyzed briefly,and the evaluation model has been established by Mathmatica.The sensitivity factors for development of water flowing fractured zone were evaluated comprehensively based on AHP-entropy weight theory so as to evaluate the safety of water inrush during mining and put forward the corresponding security measures.This research indicated that groundwater and mining thickness are the uppermost factors which affect the height of the water flowing fractured zone,and next is the coefficient of hard rock.There is an exponential increase relationship between groundwater level and the height of fractured zone,the quadric relationship between mining thickness and the height of fracture zone is approximately apparent.Therefore,controlling mining thickness and leaving waterproof coal pillar can significantly reduce the height of water flowing fractured zone,optimization of working face will be beneficial to further reduce the water inrush disaster.The method of mine roof flood prevention is enriched by this research.It has practical guiding significance for the safety production of deep mine under water body.

Key words: AHP, Entropy weight method, Water flowing fractured zone, Water inrush, Sensitivity analysis