According to the regulations and rules of coal mine water control in China,water inrush coefficient is commonly used to evaluate and predict the risk of water inrush from floor of shallow coal seam. Based on the theory of water inrush coefficient, the space superposition function of ArcGIS is applied to the calculation of water inrush coefficient. Namely, water inrush coefficient can be get by establishing thematic maps of hydraulic pressure and thickness of water-resisting floor respectively and making overlay calculation. According to the critical value of water inrush coefficient and by the natural grading method, zoning map of water inrush risk is divided into. The results show that the calculation method of water inrush coefficient by GIS is accurate and effective, and it provides a new way for the calculation of water inrush coefficient.