Potassium prolinate + water + ethanol (ProK/W/Eth) solution has potential use as a liquid-to-solid phase-changing absorbent for energy-efficient CO2 capture process. In this study, the equilibrium solubility of CO2 in ProK/W/Eth solutions was measured in a stirred equilibrium cell at a temperature range from 293 to 343 K and CO2 partial pressures up to 200 kPa. Density and viscosity were also measured at temperatures from 293 to 333 K and ProK molality up to 6.09 molkg(-1) ethanol. Moreover, the CO2 loading and cyclic capacity were compared with aqueous monoethanolamine (MEA) and aqueous ProK solution. The solubility data were well-represented using a Soft model with AAD within 8.0%. The data of density and viscosity were also correlated with empirical models. The predicted results matched well the experimental data with AAD within 0.37% for density and 1.38% for viscosity.