This study focuses on identifying the CO2 absorption mechanism in an aqueous potassium carbonate (K2CO3)/homopiperazine (homoPZ) solution, at various CO2 loading. H-1 nuclear magnetic resonance (NMR) and C-13 NMR measurements were conducted at 295 K within the absorbent concentration of homoPZ 7.5 wt % and K2CO3 15 wt %/homoPZ 7.5 wt %. The CO2-loaded absorbents were prepared by using vapor-liquid equilibrium (VLE) apparatus at 333 K The results show that the amount of carbamate and bicarbamate in the CO2-loaded K2CO3/homoPZ solution was larger than in the homoPZ, solution. The free homoPZ that is able to react with CO2 increases in the aqueous K2CO3/homoPZ solution because the. K2CO3 serves as a buffer. It was found that the NMR method can be used to determine the CO2 absorption mechanism of the absorbents.