［Objective］ To address the corrosion-induced failure of Q420NH weathering steelused in power grid towers during service，an epoxy anti-corrosion coating with both excellent corrosionresistance and corrosion-inhibition self-healing capability was developed to improve the long-termprotection of tower steel structures.［Methods］A composite filler loaded with corrosion inhibitor 5-amino-2-mercaptobenzimidazole（AMB） was prepared by a one-step method. Then，it was incorporated into an epoxy coating，and applied onto the surface of Q420NH steel to construct a composite anti-corrosion coating. The morphology and composition of the composite filler were characterized，and its corrosion inhibition effect，as well as the corrosion resistance and self-healingperformance of the coating，were evaluated through release experiments，corrosion morphologyobservation，and electrochemical tests.［Results］ The composite filler had a particle size about 100 nm，and the inhibitor loading was 17. 5%. When the addition amount of the composite filler was nomore than 2%，the corrosion resistance of the epoxy coating was effectively maintained，with the low-frequency impedance modulus remaining above 10¹⁰ Ω ·cm² after 60 days of immersion in saline solution. For the scratched coating containing 2% composite filler，the low-frequency impedance modulus remained higher than 10⁵ Ω ·cm² after 168 h of immersion，the corrosion products in the scratched region were significantly reduced，and the characteristic Raman peaks of AMB were detected.［Conclusion］ The incorporation of 2% composite filler can effectively enhance the protectiveperformance of the epoxy coating on Q420NH steel and endow the coating with excellent corrosion-inhibition self-healing capability.