In the process of mining Carboniferous coal resources in China’s coal mines, catastrophic water inrush from the floor often occurs. The water inrush source is mainly the fifth limestone aquifer of Carboniferous or Ordovician limestone aquifers. Conventional elements cannot effectively identify the source of water inrush as limestone aquifers of different geological ages. Against the background of floor water inrush in Baizhuang Coal Mine in Feicheng Coalfield, water samples of the fifth-layer limestone aquifer, Ordovician limestone aquifer and water inrush point water samples of Feicheng Coalfield were collected. Trace components F⁻, Br⁻, I⁻, H₃BO₃ and Rn were selected for compositional analysis. The minimum deviation method was used to combine and weight the weights obtained by the entropy weight method, principal component analysis method and analytic hierarchy method. An improved grey correlation model was established for water inrush source identification. The model discrimination result shows that the water inrush source comes from the Ordovician limestone aquifer, and the discrimination accuracy is high.