Studying the law of sedimentary water control of aquifers is crucial for correctly understanding the water-richness of aquifers. This knowledge ensures the safe, efficient, and environmentally friendly mining of coal seams. To address the insufficient research on sedimentary control mechanisms in loose pore aquifers, this study focuses on the bottom aquifer of the Cenozoic loose layer (called the Bottom Aquifer) in Xutuan Mine, Huaibei Mining Area, China. It analyzes sedimentary facies/ subfacies /microfacies characteristics of the Bottom Aquifer, the contact types and connectivity of the sand bodies in the vertical and horizontal dimensions, and combines water physical property testing and pumping test results to discuss the relationship between sedimentary characteristics and water-richness. The research unveils the sedimentary control mechanism influencing water-richness in the Bottom Aquifer, establishes sedimentary water control modes, and proposes the superimposed replenishment mode of fan middle subfacies sand bodies in the alluvial fans of groundwater in the Bottom Aquifer to address the phenomenon of water inrush at the 32 mining areas of Xutuan Mine, where the amount of water inrush is not large, but the duration is continuous. The results provide a scientific basis for the prevention and control of water damage in the Bottom Aquifer.