Abstract: As the mining mineral resources of the Juji Coal Mine are deepened, the problem of water damage in coal seam floor becomes more and more prominent. Based on Surfer application software and combined with AHP vulnerability index method, the threat of water inrush from the floor of Taiyuan formation limestone the research area was evaluated. Three analysis levels and evaluation index system were established, and the weight of each impact factor was determined. According to the natural classification method, from vulnerable to relative safe, the water inrush evaluation area was divided into five areas. The results show that the evaluation results are consistent with the actual situation and are relatively reliable. It provides a basis for the development of a special floor water prevention and control scheme for the Juji Coal Mine, and also updates the methods for the water damage assessment of the floor.