The invention belongs to the field of CO2 adsorption capturing, and more specifically relates to a deep eutectic solvent used for removing carbon dioxide in air and flue gas. The deep eutectic solventis composed of a hydrogen bond donor and a hydrogen bond acceptor; the hydrogen bond donor and the hydrogen bond acceptor are connected through hydrogen bonds so as to form the binary or the ternarydeep eutectic mixture, wherein the hydrogen acceptor is one selected from calcium chloride, ammonium chloride, calcium chloride dehydrate, and zinc chloride; the hydrogen donor is one or a mixture oftwo ingredients selected from ethanolamine, diethanolamine, triethanolamine, diethylenetriamine, N, N-dimethyl ethene diamine, 1, 5-diazabicyclo[4, 3, 0]-nonyl-5-ene. The deep eutectic solvent is prepared through stirring mixing at a temperature of 30 DEG C or higher, is capable of accelerating reaction speed with carbon dioxide, increasing absorption amount, reducing desorption energy consumption, and increasing carbon dioxide adsorption capturing efficiency effectively.