Waste carbonaceous catalyst (WCC) from vinyl chloride monomer (VCM) production is a potential environmental threat due to the mercury toxicity. Microwave heating (MWH) was used to decontaminate WCC. Treatment temperature had a stronger influence on mercury removal than that of treatment time while mercury removal was highly depended on treatment time at lower temperature. When WCC was treated at 350 °C for 60 min, 400 °C for 30 min and 450 °C or more for 10 min, leaching toxicity of mercury conformed to the US EPA standard. 99.98% of total mercury was removed and residual mercury concentration was only 4.5 mg kg-1 when treated at 500 °C for 30 min. Soluble and exchangeable Hg and Hg combined with labile organics were more easily to be removed than that of Hg bound to crystalline Fe/Al oxides, Hg combined with non-labile organics and HgS. The removal limit for different mercury species may be achieved at 500 °C. Evaporation removal of mercury followed exponential decay model. Activation energy for mercury removal was reduced due to the catalytic effect of MWH. Removal mechanisms of mercury included thermal evaporation, breakdown of molecular bonds, selective stripping of carbonaceous impurities.