Oxy-fuel combustion of coal is an advanced technology for CO2 control. The influences of concentrations of CO2 SO2, and H2O on arsenic removal by Fe2O3/gamma-Al2O3 sorbent in coal oxy-fuel combustion were investigated. The overly high CO2 concentration in oxy-fuel combustion inhibited the adsorption process, while addition of O-2 or H2O(g) could accelerate this process. With the increase of SO2 concentration, the removal efficiency of gas-phase arsenic first increased and then decreased. When SO2 concentration reached 8000 ppm, the arsenic adsorption efficiency was maximal. An adsorption mechanism according to the experiment phenomena was proposed to follow the Mars-Maessen mechanism. XPS characterization results indicated that the arsenic adsorption affected the charge distribution of sorbent. It reveals that electron transfer would occur between substrate and adsorbate in the adsorption process.