Abstract: The kinetic characteristics of catalytic coupling of carbon monoxide to diethyl ox-alate m gaseous phase on Palladium catalyst were studied on the basis of industrial application. The controlling step of reaction rate is adsorption of carbon monoxide. Moreover it was considered that the alkoxycarboxide intermediate COOR possibly existed, further associated to diethyl oxalate. The kinetic equations of mechanismic model were proposed. The reaction mechanism was also discussed according to reaction mechanismic model.