Abstract: Aimed at the heterogeneous characteristics of aquifer in floor, the paper established a non uniform hydrostatic mechanical model and a fluid-solid coupling model for aquifer in floor. According to the "three zone" theory and elastic-plastic theory, it obtained the elastic and plastic solutions for limit pressure of water inrush in protection zone of floor. We used the software FLAC3D to carry out numeric simulation of fluid-solid coupling of the disturbed coal face, studied deeply the characteristics of stress destruction and infiltration in the floor disturbed by coal mining. Theoretical calculation and numerical simulation method were used to predict water inrush in coal seam floor. Research shows that the non uniform pressure model is more consistent with the engineering practice, numerical simulation method can be fast and accurate to forecast water inrush. It is of great significance for water hazard control.