This research mainly aimd at the floor aquifer water hazard problem in Yanzishan Mine of Datong Coalfield. With the increase of mining depth, the floor water hazard problem became more and more prominent. Based on the analysis of the geological and hydrogeological conditions of Yanzishan Mine in Datong Coalfield, combined with the research results and experience, the vulnerability characteristics of water inrush from coal seam floor aquifer in Yanzishan Coal Mine were analyzed by scientific and advanced methods. At the same time, the vulnerability index method was applied to obtain the vulnerability of water inrush from Yanzishan Mine floor. Based on the evaluation zoning and the vulnerability assessment zoning of aquifer water inrush, the countermeasures and suggestions for mine water control were put forward.