Abstract: The first mining face 122106 in Caojiatan Coal Mine was taken as the research object. The main water filling sources and water filling channels during the mining period of the working face are determined. Through hydrochemical analysis, we master the roof water-rich situation of the research area, and ensure the working face safe mining through the working face water inflow prediction. The results show that the main filling water sources during the mining period are the overlying Jurassic Yan’an Formation and Zhiluo Formation aquifers, and the weathered bedrock aquifers in some areas, and the main source of filling water is the water-conducting fracture zone of overlying rock. Audio frequency electric perspective method and transient electromagnetic method were used to explore the roof aquifers, and several water-rich abnormal areas were identified. Then, 3 water-rich segments were found in the roof through drilling. The water quality characteristics of different water-rich segments were judged by the combined water chemical analysis, and their hydraulic relations were analyzed. According to the hydrogeological analogy method, the water inflow after mining in the research area is predicted, compared with the actual mine, the predicted result is more accurate.