Comparing the adsorption properties and dissociation on a Pt(111) iththat ona Fe(111) surface, we have con-sidered seven coordination modes of the adsorbed binding site: $di-${sigma}$${Delta}$mupi/mu$</TEX>, 1-fbld,2-fold, and 3-fbld sites. On the Pt(111) surface, t he adsorbed binding site of carbon dioxide was strongestat the1-fold site and weakest at the $pi/mu-site.$ The adsorbed binding site on the Fe(111) surface was strongest at the di-бsite and weakest at the 3-fold site. We have found that the binding energy at each site that excepted 3-fold on the Fe(111) surface was stronger than the binding energy on the Pt(111) surface and that chemisorbed $CO_2bends$ because of metal mixing with $2piu${ ightarrow}$6a_1CO_2orbital.$</TEX>, The dissociation reaction occured in two steps, with an intermediate com-plex composed of atomic oxygen and ${pi}bonding$ CO forming. The OCO angles of reaction intermediate com-plex structure for the dissociation reaction $were115^{circ}Con$ the Pt(111), and $117^{circ}C$ on the Fe(111) surface. We have found that the $CO_2dissociation$ rea11) surface proceeds easily,with an activationenergy about 0.2 eV lower than that on the Pt(111) surface.