High-efficiency absorbent for trapping CO2 gas by membrane contactor

The invention provides a high-efficiency absorbent for trapping CO2 gas by a membrane contactor, which has favorable compatibility with an organic membrane, is easy to obtain, has low price and can stably run in the membrane contactor. The high-efficiency absorbent is a water solution containing amino acid salt and multi-amino organic alcohol. The total concentration of the amino acid salt and the multi-amino organic alcohol is 0.1 to 5.0mol/L, and the molar ratio of the amino acid salt to the multi-amino organic alcohol is 1:0.5 to 1.5.