Creating superhydrophobic interfaces on Mg alloys has been regarded a promising strategy to significantly enhance corrosion resistance for practical applications. However, the abilities to withstand external damages and strengthen anticorrosion have been pursued for a long time. Herein, a novel technique has been proposed for obtaining robust superhydrophobic AZ31B Mg alloys by integrating hydrothermal processing with tannic acid (TA)-(3-aminopropyl) triethoxysilane (APTES)/polydimethylsiloxane (PDMS) coatings for synergistically-enhanced corrosion protection (abbreviated as MgHT/TA-APTES/PDMS). First, hierarchical structures for the superhydrophobic interfaces are successfully constructed by hydrothermal processing and TA-APTES nanocomplex formation through hydrolysis, oxidation, Michael addition, and Schiff base reactions; PDMS coating is then modified and optimized with a water contact angle of 165.4° and a sliding angle of 3.4° to achieve water-repellent and self-cleaning properties. Second, chemical and physical durability and robustness of the superhydrophobic coating could be consistently maintained in chemical corrosive environments (examined by water flow impact, natural exposure, sandpaper abrasion, and water jet treatments). Third, it is remarkable that that the corrosion current density of MgHT/TA-APTES/PDMS reached a record low level of 9.931 × 10−11 A/cm2 at a high corrosion potential of 0.014 V. This work demonstrates a huge breakthrough for the electrochemical performances of the modified Mg alloys, which provides an efficient strategy to significantly improving its corrosion resistance and extending its applications in implanted electronics, biomedicine, interventional therapy for cardiovascular diseases, etc.