Nanofluid is a suspension containing nanoparticles of 1 to 100nm suspended in a conventional base fluid.Nanofluids have attracted great interest owing to their greatly enhanced thermal properties as well as potentialities for enhancing the mass transport property.This study examined the CO2 absorption and the bubble behaviors in the nanofluid.Experimental analysis was performed using the bubble type absorber.The concentration of nanoparticles and the rheological properties of the base fluid were considered as major parameters of bubble behaviors and the mass transfer performance of CO2 gas into the liquids.Rheological properties were varied by regulating the fraction of particle or addition of PMMA.The results showed that high viscous property made the initial outspread of gas bubble small and high elastic property made bubbles move to the center of column.In the absorption experiment using the 5wt% nanofluid,the absorption rate of the first 1 minute increases 79% in water and 17% in 0.05M amine solution.The total absorption amount increases 0.16 L in water and 0.38 L in amine solution.Nanoparticles in nanofluid could crack the gas bubbles and increase the contact area between gas bubbles and liquid.Through the result of absorption performance,we suggested that nanoparficle could have surface renewal effect on gas-liquid interface,and nanofluid could intensify the reactivity between amine and CO2 component.