The absorption rate of carbon dioxide into a methyldiethanolamine (MDEA) aqueous solution blended with piperazine (PZ) under a high carbon dioxide partial pressure was studied by an experimental packed column. Also, the results indicated that the absorption rate of carbon dioxide at a high carbon dioxide partial pressure was larger than that of the calculation value from the kinetics model of atmospheric pressure because the Marangoni effect was strengthened by the elevated carbon dioxide partial pressure. The kinetics model modified by a carbon dioxide partial pressure was obtained as follows: NCO2 = fHCO2[DCO2(kMDEACMDEA + kPZCPZ)]1/2(P − P*), where f = 0.83[ln(P/100)]0.8 + 1.0 and 100 kPa ≤ P ≤ 625 kPa. The simulation of a commercial absorption column has verified this modified model successfully.