The adsorption abilities for vapor-phase Hg-0 by a Ca-based sorbent were investigated in an attempt to produce more effective sorbents for the control of elemental mercury emission. Ca(OH)(2) and Mnx+ doped in Ca(OH)(2) have been characterized by surface analytical methods, such as Brunauer-Emmett-Teller (BET) surf ice area, scanning electron micrographs (SEMs), energy-dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The mercury adsorption characteristic was also revealed by XPS. The results showed that mercury removal by Mnx+/Ca(OH)2 was a bit higher than that by Ca(OH)(2). From mercury speciation measurement, Hg-0 could be oxidized by MnO2 effectively. From XPS analysis, there was a peak corresponding to the divalent mercury. Thus, there was oxidized mercury on the surface of Mnx+/Ca(OH)(2). The presence of MnO2 affected mercury speciation.