To solve the problems of desulfurization capacity reduction caused by monoethanolamine (MEA) deterioration in the COG desulfurization system, and the increased consumption of MEA due to thermally stable salts generated in the process, physical properties of the amine liquid and its major composition are determined through physical and chemical analysis of desulfurization of amine liquid.The thermally stable salt content of amine solution in desulfurization system can be maintained around 1% by the dynamic amine solution purification process of filter element-activated carbon-anion exchange resin.