The work aims to improve the adhesion of hydrophobic coating by electrostatic spraying. Hydrophobic silica powder was prepared by surface modification of silane coupling agent and poly two methylsiloxane. Mixed hydrophobic powders were prepared by mixing a certain proportion of polyvinylidene fluoride (PVDF) and ultra-high molecular weight polyethylene (UHMWPE) with hydrophobic silica powder. Epoxy resin, curing agent and active agent were used to prepare the conductive expoxy resin. Hydrophobic composite coatings of aluminum alloy were prepared by electrostatic spraying on the surface of aluminum substrate covered with conductive epoxy resin. The hydrophobic composite coatings were tested and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle tester and Bagram knife adhesion tester. From SEM results, the coating surface had a micro-nano hierarchical rough structure, and the modified surface had good hydro-phobicity by CA test. When the proportion of polydimethylsiloxane modified silica in the mixed powders was 20%, the contact angle of epoxy-based hydrophobic coatings reached 140°, the rolling angle reached 5°, and the adhesion grade was 0. At the same time, the hydrophobic coatings had good wear resistance and corrosion resistance. Hydrophobic coatings with high adhesion are prepared by simple and industrialized electrostatic spraying process and has a wide application prospect.