A new sulfolane/secondary amine biphasic absorbent, sulfolane/2-methylaminoethanol (MAE) solution, was developed for postcombustion CO2 capture (PCC). Surprisingly, using a 4M/SM sulfolane/MAE solution saves about 60% energy consumption (EC) for CO2 stripping when compared with traditional aqueous SM monoethanolamine (MEA) solutions. First, we theoretically proved that MAE in sulfolane-based biphasic solution improves the CO, absorption rate with high CO2 loading at the phase-changing point, which could be energy-saving for CO2 stripping. Based on a comprehensive comparison of the phasechanging behavior, nuclear magnetic resonance (NMR) spectra, absorption rate, and desorption performance, the 4M/SM sulfolane/MAE was determined to be the optimal molar ratio among six sulfolane/MAE biphasic solutions for CO2 capture. In addition, the absorption and desorption experiments with various temperatures revealed that relatively low temperature (ranging from 110 to 120 degrees C) was favorable for CO2 removal and energysaving. Furthermore, the 4M/SM sulfolane/MAE solution achieved a very low energy consumption (EC) compared with that of SM MEA solution, and the stripped CO2 amount is similar to that of SM MEA and SM MAE solutions.