In the mining process over the years of No.1 mine in Henan Pingyu Coal and Electricity Co., Ltd., the safety mining was threatened by the Cambrian limestone water in the floor. The well flooding accident occurred because of Cambrian limestone water outburst. Therefore, before the excavation of the mining project, it was necessary to formulate a treatment plan for the Cambrian limestone water in the floor to treat the Cambrian limestone water to achieve the excavation conditions under pressure. It was the key to determine the treatment layer and depth in the Cambrian limestone water treatment scheme. In this paper, through the calculation and research on the depth of the floor failure zone, the thickness of the effective aquifuge and the water outburst coefficient of the floor water after the mining of the coal seam in No.1 mine, the depth and layer of the floor water treatment were comprehensively determined, which provided experience for the treatment of Cambrian limestone water under similar conditions.