A novel multi-amine functionalized IL ([APmim] [Lys]) had been developed for CO, capture in the present work, in which the amine and lysine functionalized groups were both introduced to the imidazole ionic liquid (IL). The CO2 absorption loading of the saturated [APmim] [Lys] solution was found to be 1.80 mol of CO2/mol of ILs (6.71 mol of CO2/kg of IL, 26.7 wt % CO2), which was much higher than other functionalized ILs solutions. The viscosity of [APmim] [Lys] (0.5 mol/L) was found to be 0.8 mPa/s at 323.15 K, which was just 1.25 times that of MEA solution, and was much lower than that of pure ILs. The optimal regeneration temperature of the solvent was 120 degrees C, and the regeneration efficiency after the fifth thermal desorption even kept at 99.1%. The structures of [APmirn] [Lys] with or without water were estimated by quantum chemical calculations, and the difference in the structures was reflected by the viscosities of the ILs. The results of the characterization by FT-IR and C-13 NMR indicated that CO2 capture into [APmim] [Lys] with or without water was different processes. In pure ILs, CO, reacted directly with [APmim] [Lys] to form carbonate salt. In aqueous solution, it started with an exothermic reaction to form carbamate, followed by a hydrolysis of carbamate, and then finished with an endothermic reaction by hydrolysis.