The main components of books and ancient books are organic substances such as animal and plant cellulose, hemicellulose and lignin. These substances easily react with oxygen or corrosive gases in the air and are damaged by oxidation, photooxidation and hydrolysis. Eventually, paper materials will age and deteriorate. Using the technology of low oxygen atmosphere, the oxygen and harmful gases in the closed space where books and ancient books are located can be replaced by clean nitrogen, which reduces the probability of oxidation, acidification and hydrolysis of books and ancient books, thus slowing down their aging speed and prolonging their preservation period.