First, several fluorinated silsesquioxane-based giant molecules (G-SQs) were easily prepared by the photo-initiated thiol-ene click reaction of octa(mercaptopropyl)silsesquioxane (SH8-SQ) with monovinyl(heptatrifluoropropyl)silsesquioxane (CF3-SQ) and perfluorohexyl ethylene with varying stoichiometric ratios. Then, G-SQs were used as low surface energy substances to modify epoxy acrylate resin (EA), which allowed adhesion to different substrates to prepare hydrophobic coatings via photo-initiated thiol-ene click reaction. The hybrid coating can impart stable superhydrophobic properties to cotton fabrics, which possess self-cleaning and oil–water separation function. The cotton fabrics coated by G-SQs-EA can perform oil–water separation very well, whose oil–water separation fluxes and efficiencies are 34,000 L m−2 h−1 and 99 %, respectively. The hybrid hydrophobic coating also provides effective corrosion protection for copper and the corrosion protection effect is further improved by increasing coating thickness. The corrosion current density, corrosion rate and impedance (0.01 Hz) reached 1.17*10−2 μA·cm−2, 0.14 μm yr−1 and 1026 kΩ cm−2, respectively. These excellent results indicate that EA coating modified by G-SQs has potential applications in many fields.