Abstract: Identifying the fault structures that control groundwater circulation and quantitatively evaluating the respective contributions of individual faults to geothermal groundwater recharge and discharge are fundamental to understanding geothermal flow systems. Such information is critical for optimizing geothermal resource exploration, sustainable production, and artificial recharge strategies. In this study, continuous pore-pressure monitoring was conducted in a confined geothermal aquifer within the Xiaobu geothermal field. Based on the hydrogeological response of groundwater to solid Earth tides, fault-induced pore-pressure signals were extracted from the monitoring records. The relationship between fault-related pore pressure and volumetric strain induced by solid Earth tides was analyzed, and a mathematical model was developed to quantify the strain associated with faults of different orientations and their respective contributions to groundwater pressure variations. The proposed framework was subsequently applied to evaluate the recharge and discharge functions of the major faults in the Xiaobu geothermal system. The results show that the fracture water pressure is monotonically linearly positively correlated with the volume strain, with a correlation coefficient of 0.915 1 and an R² value of 0.837 4; F1 contributes the most to discharge of geothermal water (26.26%) while also providing a substantial contribution to recharge (20.18%). In contrast, F5 was identified as the dominant recharge conduit, contributing 21.11% of total recharge and 19.38% of total discharge. Fault F2 made a relatively large contribution to discharge (19.58%) but the smallest contribution to recharge (17.82%). F3 and F4 contribute comparatively greater recharge of geothermal water (20.45% and 20.43%, respectively), and the least discharge (17.58% and 17.20%, respectively). F1 and F5 are the main controlling structures of Xiaobu geothermal water, but the priority of recharge and discharge functions is different. F1 has the largest discharge contribution rate and the smallest variation coefficient, making it the preferred object for expanding geothermal water production; F5 has the largest recharge contribution rate and the largest variation coefficient, making it the preferred object for geothermal water recharge. The results have practical significance for the recharge and increase production of Xiaobu geothermal water.