The invention discloses a preparation method of a super-hydrophobic polyvinylidene fluoride microporous membrane. The method comprises the steps that firstly, a one-step solution soaking method is used for obtaining a super-hydrophobic magnesium alloy surface, a metal plate is soaked with a mixed solution composed of a ferric chloride water solution and a fatty acid ethanol solution, a long-chain fatty acid salt depositing layer with the low surface energy is deposited on the surface of a magnesium plate through a reaction of the soaking solution and magnesium, the metal plate is adopted as a membrane preparing substrate, the membrane is prepared by adopting a water vapor induction-gel immersion method, the rough structure on the surface of the magnesium alloy plate can be partially rubbed to the surface of the membrane, and low-surface-energy materials on the surface of the magnesium plate are transferred and stuck to the surface of the membrane, so that the surface hydrophobicity of the membrane can be greatly improved, and the super-hydrophobic effect is achieved.