Contact-electro-catalysis (CEC) converts mechanical excitation into interfacial redox chemistry, yet polar mineral water interfaces remain insufficiently engineered, limiting the efficient translation of spontaneous polarization into contact driven charge transfer. Here, we use surface hydroxylation to regulate the polar interface of natural tourmaline for enhanced CEC. Experiments and first principles calculations show that hydroxyl groups preferentially anchor at surface Al sites, forming a hydroxyl enriched interface while preserving the bulk crystal framework. This interface reorganizes the charge distribution, enhances effective interfacial polarization, raises the surface potential, and reduces charge transfer resistance, thereby facilitating H2O and O2 activation. Under ultrasound excitation, hydroxylated tourmaline produces ·OH and ·O2− signals 6.5 and 5.7 times higher, respectively, than those generated by spontaneous polarization alone. The enhanced CEC enables Rhodamine B degradation, heavy metal removal, and antibacterial activity. This work establishes hydroxylation regulated polar interfaces for mechanically driven environmental catalysis.