Display omitted •H2O interacts strongly with ChoPro/PEG200 in the hybrid absorbent.•The formation of carbamate is dominated especially at low CO2 pressure.•The presence of H2O results in the formation of bicarbonate.•The hybrid absorbent has advantages on the CO2 solubility and absorption enthalpy. Developing novel hybrid absorbents is essential for CO2 separation. In this study, the density and viscosity of a hybrid absorbent (choline-2-pyrrolidine-carboxylic acid/polyethylene glycol/water (ChoPro/PEG200/H2O)) were measured experimentally, and its CO2 solubility was also determined. The excess mole volume and excess Gibbs energy of activation of the hybrid absorbent were further estimated to understand the molecular structure and interactions between ChoPro/PEG200 and H2O. The CO2 solubilities in ChoPro/PEG200 and ChoPro/H2O were analyzed and described using the Redlich–Kwong non-random-two-liquid (RK-NRTL) model. Furthermore, the CO2 solubility in the hybrid absorbent was predicted using the RK-NRTL model and was compared with the new experimental results for verification. The effect of H2O on the CO2 absorption performance was further analyzed. The performance and cost of the hybrid absorbent were compared with those of other commercialized CO2 absorbents. In addition, the recyclability of the hybrid absorbent for CO2 separation was studied. The results of this study indicated that the hybrid absorbent could be promising for CO2 separation.