High-voltage switchgear is one of the core electrical equipment in distribution network. In actual operation, due to the limited sealing degree of the high-voltage switchgear, moisture from the external environment will inevitably infiltrate into the interior. When the metal surface is damp for a long time, in the complex electromagnetic environment of high electric field and high current, combined with oxygen and carbon dioxide in the air, various types of electrical and chemical corrosion will inevitably occur, resulting in switchgear failure. In this paper, different surface treatment technologies were used for the important contact parts in the high-voltage switchgear, and the corrosion resistance of the copper contacts after treatment was analyzed. The test results showed that after the metal coating and surface passivation treatment, the mass of patina on the copper contacts was significantly reduced, and the corrosion inhibition rate could reach about 85% at high humidity, which indicated that appropriate surface treatment technologies could greatly improve the corrosion resistance of copper contacts and reduce the failure rate of high-voltage switchgear in humid areas.