Abstract: Aiming at the contradiction between the needs of driving floor gas drainage roadway at Zhaogu No． 2 coal mine to control gas and the risk of floor water inrush caused by driving the floor gas drainage roadway above the con- fined aquifers,by using the boundary equation of plastic zone in circular roadway surrounding rock under the influence of confined aquifers,the relationship between the distribution characteristics of the plastic zone of the surrounding rock and the risk of the floor water inrush is analyzed. By using the numerical simulation,two facts are studied:the stress distribution in the floor after working face excavation,the failure characteristics of surrounding rock and the corre- sponding risk of floor water inrush when the floor gas drainage roadway is arranged at different positions. The results show that the non-uniform distribution of plastic zone of the floor gas drainage roadway’s surrounding rock will signifi- cantly reduce the thickness of the floor aquiclude and increase the risk of floor water inrush. After the working face ex- cavated,the stress of the floor can be divided into four regions according to the ratio of the two-way stress and the stress loading and unloading state. According to the impact on the floor water inrush,the danger can be ranked as:high and unloading stress ratio area > stable and unloading stress ratio area > low and loading stress ratio area > original rock stress ratio area. In view of the above,the rational location of the floor gas drainage roadway in Zhagou No. 2 coal mine should be arranged along the normal direction of the working face and driven under the middle of coal pillar and along the sandy mudstone layer’s bottom which is above the L9 limestone.