The formation of Sr-rich mineral water in magmatic rock-fault systems cannot be attributed solely to leaching from a single lithology, but is jointly controlled by Sr-rich source rocks, fracture-flow systems, and hydrochemical conditions favorable for Sr preservation. Taking the Shilingxiu mineral-water source area in Xiahuayuan, Zhangjiakou, as a case study, this study integrates shallow geophysical surveys, hydrochemical and rock geochemical analyses, and hydrogeochemical modeling using the PHREEQC software to elucidate the role of the fault-syenite contact zone in controlling Sr release, migration, and enrichment. The results show that the upper 300 m of the study area contains a heterogeneous bedrock-fracture system composed of shallowly buried syenite, fractured andesite, Mg-type water in which Sr occurs predominantly as free Sr²⁺. Celestite is markedly undersaturated, indicating that the prevailing hydrochemical conditions favor the migration and preservation of Sr in dissolved form. Calcite is near equilibrium, whereas dolomite is supersaturated, suggesting that carbonate mineral precipitation may constrain further Sr enrichment. Syenite porphyry has an average Sr content of 764×10^-6 and represents an important potential source rock for groundwater Sr enrichment. Faulting controls the shallow burial of syenite, the distribution of contact zones, and fracture connectivity, thereby locally coupling silicate weathering, carbonate dissolution, and valley-controlled discharge boundaries. The Sr-rich mineral water in the Shilingxiu source area is therefore classified as low-temperature, leaching-derived bedrock-fracture groundwater controlled by the fault-syenite contact zone.