<p>When magnesium alloys are used in daily life and industrial fields, their poor corrosion resistance must be considered. Superhydrophobic coatings, due to their unique properties, offer positive corrosion protection. In this paper, a chemical etching method was employed to fabricate blade-like micro-/nanostructures on the surface of AZ91D magnesium alloy, followed by FAS (1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane) modification. This process ensures that the magnesium alloy surface meets the requirements for the micro-/nanostructure and low surface energy necessary to form a superhydrophobic coating. The coating shows superior superhydrophobic properties, with a static contact angle of 161° and a sliding angle less than 3°. It also demonstrates outstanding self-cleaning and water-repellent performance against all kinds of contaminants, effectively preventing contact with corrosive solutions and improving the corrosion resistance of the magnesium alloy surface. To better comprehend the self-cleaning mechanism, we analyzed the forces acting on contaminant particles on the inclined superhydrophobic surface. By theoretical analysis, we built a mathematical model describing the self-cleaning process of the surface, providing a comprehensive explanation of the self-cleaning mechanisms. Additionally, electrochemical measurements indicate the coating has good corrosion resistance, characterized by a high corrosion potential (<i>E</i>_corr) and low corrosion current density (<i>I</i>_corr).</p> Graphical Abstract <p></p>