This paper proposes a new kind of aquifer criterion to determine the permeable fractured zone's height after working face mining. The new criterion can be explained as follows. It is shown that if the permeable facture zone's height is monitored by the measuring instrument, one may see the designed drill break across the aquifer upon the fractured zone. Then the confined water would flow down through the drill. This phenomenon shows that the permeable fractured zone has not been developed to the height of the aquifer layer. So, whether the aquifer layer is destroyed may be taken as a new kind of criterion to determine the height of the permeable fractured zone. With this new criterion, one must analyze the layer relationship between the permeable fractured zone and the aquifer based on the reasonable prediction of the permeable fractured zone's height. According to the regression analysis of measured results of some coal mine's permeable fractured zone height, the new criterion is shown to be more accurate and safer in determining the permeable fractured zone's height.