Two layers of coal seams (No.1 coal seam and No.4 coal seam ) are widely developed in Binchang mining area. Under the condition of repeated mining of multiple coal seams, there is a large amount of water in the goaf of the overlying No.1 coal seam, and because the water-conducting fracture leads to the strong water-rich aquifer of the Luohe Formation, the pre-mining drainage of the lower coal seam faces the dual governance problems of the static reserves of the overlying goaf and the dynamic replenishment of the aquifer. Taking ZC1402 working face of Yadian Coal Mine as the research object, there is ZC1101 goaf in its roof, which is a typical repeated mining working face. The design of “secondary drainage” of roof goaf water in repeated mining working face and the dynamic monitoring of water quantity and water pressure in the whole process are carried out, and the dynamic evolution characteristics of drainage water quantity, water pressure and water level are systematically analyzed. The results show that the roof ZC1101 goaf water (static reserves) is about 2.97×106^m3^{, Luohe group dynamic recharge is 152m}3^{/h; cumulative discharge 3.1289}×106^m3^{, more than static reserves 1}.589×105^m³; on the scale of drilling field, the cumulative drainage volume of S1~S3 drilling field is about 2500m³, and the stable water inflow is about 110m³/h. The cumulative drainage volume of the drilling field along the transportation channel is about 210m³, and the stable water inflow is about 9m3^/h. On the whole, the total water inflow was 2924.53m³/h in the early stage of drainage, and stabilized at 240m³/h in the later stage. The water pressure of the return air crossheading is reduced from an average of 0.5MPa to 0.13MPa, and the water pressure of the transport crossheading is reduced from 0.35MPa to 0.081MPa. The water level of each drilling field is lower than that of the goaf floor. The whole drainage process is characterized by the two-stage characteristics of “rapid drainage of static reserves and stable supply of dynamic replenishment”. In the first stage, the static reserves are mainly discharged, the water inflow is rapidly attenuated and the water pressure is greatly reduced. The second stage is dominated by dynamic recharge, which is characterized by relatively stable water volume and low water pressure. This law reveals the relationship between the duality of water source composition and the sequence of drainage under repeated mining conditions. The research results can provide a quantitative design basis for the prevention and control of water disasters in repeated mining working faces.