There is a hidden water guide sink column under the floor of 1-101 working face of Yilong Coal Industry. In order to ensure the safe recovery of the working face, the numerical model was established to simulate the stress and deformation of the floor under the mining face. The displacement was measured, and it was found that the stress and plastic zone of the floor increased with the decrease of the distance from the sinking column, and the collapse of the sinking column occurred shear failure, resulting in a water conduction crack between the floor and continuous advancement may cause The occurrence of work water inrush accident, for this reason, the grouting water blocking technology was used to transform the bottom plate and related areas. After the transformation, the maximum water pressure after inspection was 0.75 MPa, and the maximum water influx was 6.3 m3 / h, thus ensuring the safe recovery of the working face.