<p>Pb-Sb alloy is an excellent cutting rope material, however, easy to be corroded in CO₂-containing environment. Hereby, the Pb-Sb alloy was heat-treated, and its microstructure and corrosion behavior in H₂CO₃ solution were investigated. The morphology and chemical composition were characterized with scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy, and x-ray diffractometry. The corrosion resistance of the samples has been measured by electrochemical and immersion tests. The hardness of the samples was also measured. The results showed that Sb was basically integrated into the Pb matrix after solution treatment at 290&#xa0;°C for 1&#xa0;h, and the grain size increased an order of magnitude. After aging treatment at 100&#xa0;°C for 2&#xa0;h, the hardness and corrosion resistance of the Pb alloy reached the highest, and the grain size of the alloy was larger than that of the original state, but was finer and more uniform than that of the samples after solution treatment and aging treatment for longer time due to the recrystallization. The decrease in the amount of large secondary phases and grain boundaries resulted in the improvement of the compactness of the corrosion products layer formed on the alloy surface during the corrosion test. In contrast, the excess of dispersed and fine secondary phases and coarser grains led to less protective corrosion products film and lowered the corrosion resistance after the solid-solution or longer-time aging treatment.</p>