<p>The stabilities of oxide films on the surface of titanium alloys could determine their corrosion resistance values. Therefore, high-concentration NaCl solutions containing different corrosive species (CO₂, H₂S, and CO₂/H₂S) were simulated by molecular dynamics to study the interfacial corrosion characteristics of titanium oxide (TiO₂) film on a TC4 titanium alloy in this article. The corrosion mechanism of the titanium alloy was explored based on the system equilibrium criterion, interfacial binding energy, mean square displacement (MSD), radial distribution function (RDF), and relative concentration distribution. The results showed that the degrees of corrosion of the different species on TiO₂ were in the order of Cl^- &gt; HS^- &gt; HCO₃^-. Cl^- was first adsorbed on the surface of TiO₂, and its adsorption was the most stable. The concentration distribution map showed that Cl^- penetrated the interior of TiO₂, leading to the dissolution of the local oxide film. HS^- and HCO₃^- were mainly distributed on the surface of TiO₂, accelerating the destruction of the surface oxide film. Adding a small amount of H₂S gas in the CO₂-Cl^- environment inhibited the CO₂-based corrosion of the titanium alloy, and H₂S corrosion dominated. An increase in the H₂S partial pressure accelerated the concentration of HS^-, increasing the corrosion rate, and the facial film of titanium alloy changed from TiO₂ to TiS₂, further degrading the degree of protection that the film layer provided to the TC4 titanium alloy.</p>