This chapter delves into the mechanism of water inrush in coal mine floors, employing microseismic monitoring, theoretical analysis, and numerical simulation, with the Dongjiahe Coal Mine as a representative case study. It begins by establishing the research background and significance, followed by a detailed literature review that examines global and domestic studies on water inrush mechanisms and monitoring methods, thereby identifying critical gaps in current knowledge. Building on this foundation, the chapter explores the stress field and failure characteristics of the coal mine floor, integrating elastic mechanics theory, numerical simulations, and microseismic monitoring to uncover the interactions between stress distribution and structural failure. Attention is then directed to the development of water inrush channels, analyzing stress variations and the evolution of stress fields in fault-influenced surrounding rock. Further, the study investigates the failure characteristics of floor faults above confined aquifers through mechanical modeling, stress field solutions, and numerical simulations, supported by microseismic observations of fault damage. The integration of these approaches provides a coherent understanding of the processes driving water inrush and offers actionable insights for predicting and mitigating such hazards in coal mining, ensuring both safety and operational efficiency.