The amine solution is characterized by quick absorption,large absorption capacity and simple regeneration. The potentiometry method and pH method were used to study carbon dioxide absorption characteristics in MEA, DEA and TEA solution. The relations among electric potential, pH, absorption rate, absorption capacity were studied. The new measurement methods about amine solution concentration and carbon dioxide concentration were presented. The results show that MEA and DEA are good amine solutions. Also after drawing the relation curve between absorption rate and potentiometry or absorption rate and pH, the potentiometry method (or pH method) can be used to analyze the absorption extent of CO2 in amine solutions.