Using the organic corrosion inhibitors was the most easy and effective means to prevent the carbon steel pipelines from CO\-2 corrosion. A vapor\|liquid phases corrosion inhibitor was obtained by mixing morpholine derivative with imidazoline derivative, thiourea and propiolic alcohol. The corrosion inhibition efficiency of complex inhibitor for N80 steel was studied by static suspension weight\|loss method. The result shows that the corrosion inhibitor had good inhibition efficiency for CO\-2 corrosion both...