Abstract：Based on the water inrush coefficient Ts，the unit inflow q，an index reflecting water bearing of the aquifer，is introduced. Based on statistical analysis of a large number of examples of water inrush，the relationships between water inrush potential，water inrush coefficient，and the water-enriched properties of aquifer are further researched. The achieved laws of water inrush are discussed. And a new method for evaluating risk of floor water inrush is put forward. The method of water inrush coefficient-unit inflow method can be a supplement for evaluating water inrush coefficients. The achieved results can be provided for evaluating water inrush risk of floor in deep mining of some mining areas，in which the water-enriched properties of aquifer are not obvious but water inrush coefficient is larger.
