Mercury catalytic oxidation technologies in recent studies are summarized in this study to highlight the present research development and future perspective of catalysts. The mercury oxidation catalysts are classified into V-based catalyst, noble metal catalyst and transition metal oxides catalyst. The mercury oxidation efficiency (MOE) of V-based catalyst strongly depends on HCl and Cl_2 concentrations in the flue gas. The noble metal catalyst (e.g., Au, Ag, Pt, Ru and Pd-based) is a promisingmercury oxidation catalyst because of its strong affinity toward mercury atom. The transition metal oxides (Cu, Mn, Fe, Mo, Ag, Pd, Cr, etc.) has also been used to develop low and middle temperature catalysts for Hg^0 oxidation. Most of these catalysts have very high mercury oxidation efficiencies at a certain temperature, but NH_3 and SO_2 in the flue gas seriously suppress the catalyst activity from 94.7%±3.9% and 83.9%±4.8% to 66.8%±16.8% and 57.1%±7.5%, respectively. It is concluded that puremetal oxides serving as single oxidation site would not be suitable mercury oxidation catalysts in the complex flue gas environment. The multicomponent metallic oxide catalysts generate more species oxidation reaction sites for NO reduction and Hg^0, which promotes the possibility of NO and Hg^0 synergic removal. This work also proposes the future challenge of highly efficient Hg0 oxidation catalyst.