Abstract: Amino acids are potentially attractive solvents for carbon dioxide capture from coal-based power stations, and present certain benefits over amines in CO2separation systems,such as low toxicity, low volatility and high resistance to oxidative degradation. This paper carried out a study of CO2reacting with glycine in aqueous media using stopped-flow pH indicator technique. The results show that the reactivity of neutral form is much less than that of base form. Density functional theory calculations at the M062X/6-31G（2df,p） level of theory demonstrate that reactivity of the neutral form is diminished by the thermodynamic instability of the zwitterion reaction product, as opposed to any raising of the intrinsic reaction barrier.