The coordinative effect in monoethanolamine (MEA) and 2-butylamino ethanol (BEA) solution can promote both CO₂ absorption and desorption. MEA+BEA binary amine system was extended to MEA+BEA+diethylaminoethanol (DEEA) ternary amine system in this paper. The CO₂ absorption-desorption performances of 0.1~0.5 mol/L MEA, 2.0 mol/L BEA, and 2.0 mol/L DEEA mixed solutions were investigated and compared with 2.0 mol/L BEA and 2.0 mol/L DEEA solution in the experimental system of absorption-desorption reactor and recirculating process. The coordinative effect was analyzed using CO₂ absorption and desorption parameters. The results show that the coordinative effect of MEA+RR'NH+RR'R''N makes MEA+BEA+DEEA better than BEA+DEEA in CO₂ absorption and desorption, and the optimum mixing molarity is 0.1 mol/L MEA, 2.0 mol/L BEA and 2.0 mol/L DEEA. It is different from the traditional MEA which enhances absorption but reduces desorption.