Abstract: The mercury evaporation rate, specific surface area, catalyst composition, and mercury form of high-, low-, and waste high-mercury catalysts in the acetylene PVC industry were tested by the dynamic flux chamber, specific surface area analyzer, scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. It is shown that the mercury evaporation rates of the high-, low-, and waste high-mercury catalysts are 1.04 × 10^-7, 5.90 × 10^-8, and 2.47 × 10^-4 mg·g^-1·min^-1, respectively. Mercury chloride is reduced to elemental mercury after the high-mercury catalyst is used, and mercury is adsorbed on the surface of the waste mercury catalyst, causing the mercury evaporation rate of the waste high-mercury chloride catalyst much higher than that of the new.