Abstract: In order to explore the hydrogeological conditions of the Cretaceous Luohe Formation in Binchang mining ar- ea,this paper proposed the Luohe Formation’ s refined exploration concepts from the perspective of water-preserved coal mining,gave a comprehensive water-rich index method which can be used to evaluate the vertical water-richness of confined aquifers. The Luohe Formation was layered according to vertical water-richness. Luohe formation’s vertical hy-drogeological conditions and characteristics,hydraulic connection between the vertical aquifers of Luohe formation before and after mining,and the significance of water-preserved coal mining of the lower aquifer of Luohe formation were studied. Calculation method of water-rich index is given as follows:the indexes of lithology,thickness and porosity are assigned,and their weights are 0. 3,0. 4,and 0. 3 respectively;the value of water-rich index (fi ) can be obtained by the cumulative multiplication of values of indexes and weights;then,the comprehensive water-rich index of each layer can be obtained using the following formula Fi = 0. 5fi + 0. 15fi -1 + 0. 1fi -2 + 0. 15fi +1 + 0. 1fi +2 . Grading stand- ards of comprehensive water-rich index for aquifers in Luohe Formation are given: F < 0. 003 289 is aqui- clude,0. 003 289≤F