The effects of the temperature, oxygen concentration, and excess oxygen coefficient on mercury oxidation under O 2 /CO 2 and O 2 /N 2 coal combustion were experimentally analyzed in a fluidized bed. The results suggested that both the concentration and proportion of Hg 0 increased as the temperature increased under oxy-coal combustion. Mercury was also primarily in elemental form at high temperatures under oxy-coal combustion. Mercury oxidation was much less effective in the presence of CO 2 . The percentages of Hg 0 and Hg 2+ increased as the excess oxygen coefficient increased under oxy-coal combustion.