Carbon dioxide adsorbent, also known as calcium hydroxide particles and soda lime, is pink or white columnar particles, loose and porous structure, large adsorption surface area, good permeability. The white particles, after absorbing carbon dioxide, become purple, and the pink particles, after absorbing carbon dioxide, become white. Its carbon dioxide absorption rate is very high, can be widely used in oxygen breathing apparatus and self-rescue device to absorb human exhaled carbon dioxide, as well as chemical, mechanical, electronic, industrial and mining, medicine, laboratory and other need to absorb carbon dioxide environment.