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The outer surface of the steel structure constitutes the main part that is painted on bridges. Given the difficulty and high cost associated with painting bridges for maintenance, it is necessary to ensure that these bridges have a long service life against corrosion. Therefore, a long-lasting anti-corrosion coating system consisting of a primer, an intermediate coat, and a topcoat is used, along with cost-effective coatings. Primer options include zinc phosphate epoxy primer, zinc-rich epoxy primer, inorganic zinc-rich primer, and hot-dip galvanizing/aluminum spraying coatings. Among them, inorganic zinc-rich primers include alcohol-soluble inorganic zinc-rich primers and water-based inorganic zinc-rich primers. Epoxy zinc-rich primers, with their excellent electrochemical protection properties and good applicability, are suitable for most coating systems. For conventional anti-corrosion systems in C3 and C4 corrosion environments, epoxy zinc phosphate primers can be used; whereas for long-life coating systems of type C5-M, inorganic zinc-rich primers or thermal zinc/aluminum spraying should be employed. The intermediate coat uses an epoxy limonite intermediate coat, which offers excellent shielding properties and mechanical strength, as well as an appropriate roughness that ensures good compatibility with the top coat. The topcoat uses highly weather-resistant topcoats; for example, acrylic polyurethane topcoats are widely used as topcoats in long-lasting anti-corrosion coating systems due to their excellent weather resistance. In harsh corrosive environments (C5), cross-linked fluorocarbon coatings and polysiloxane coatings can be employed.