Abstract: To clarify the mechanism by which Pb content affects the corrosion behavior of brass in Cl^--containing environments, immersion test, electrochemical impedance spectroscopy (EIS) test, and micro-morphology characterization were used to investigate the electrochemical corrosion behavior of brass with three different Pb mass fractions (0%, 0.025%, and 2.6%) in a 3.5% NaCl solution at room temperature. The results show that Pb-containing brass formed lead-based compounds PbCO₃, Pb₃(CO₃)₂(OH)₂ in the early stage of corrosion, which deposited on the substrate surface and inhibit dezincification by hindering charge transfer, thereby improving corrosion resistance. As corrosion progressed, the 0.025% Pb brass developed a dense Cu₂O film structure on its surface, which maintained excellent corrosion resistance. In contrast, the 2.6% Pb brass exhibited significant dissolution of the Pb phase, causing the lead-based compounds to detach and making it difficult to form an effective, dense protective film. This was accompanied by abnormal accumulation of copper-zinc corrosion products, resulting in a substantial decrease in corrosion resistance. Although Pb-free brass can also form a Cu₂O film, dezincification continues to occur in the substrate, placing its corrosion resistance between the two Pb-containing brasses.