Abstract: During the mining of No.3 coal seam,the No.1 mine section of Jining III mine field is threatened by the water-inrush from the overlying aquifers like roof sandstone,red beds of Jurassic period,lower formation of Quaternary system and so on.Based on the hydrochemical methods and the water quality materials,hydrochemical characteristics of the aquifers are described,the sources of water-inrush are determined by cluster analysis methods.Red beds water and roof sandstone water are the main sources that contribute to the water-inrush in the coalface of the No.1 mine section.With the rising of mined area of the No.3 coal seam,the proportion of roof sandstone water for the water inrush develops correspondingly.Information from water inrush yield and water table confirms it is an effective way of analyzing the sources of water-inrush.