Electrochemical measurements, salt spray tests and immersion tests were employed to investigate the influence of deposition periods and corrosive medium (NaCl, H₂SO₄, HCl, NaOH) on the corrosion behaviors of silicon doped multilayer diamond-like carbon (DLC) coatings. The results showed that the corrosion resistance of the multilayer DLC coatings was significantly improved with the increase of deposition periods. Interestingly, the coating with the highest deposition periods provided good corrosion protection in neutral and acidic solutions while poor corrosion protection in alkaline and acidic chloride solutions.