After Cai Lun improved papermaking, the circulation of paper books in the Eastern Han Dynasty made great progress. Paper is used for people-to-people communication, manual transmission and writing are becoming more and more common, national and private books have been developed, and specialized bookstores have appeared in the market. It embodies the great progress of ancient books in China. Bamboo slips and silks are the main writing materials widely used in Han Dynasty. Since Cai Lun created a new idea and made new "paper" from bark, hemp, rags and fishing nets, paper has been gradually applied to folk communication activities. In the early days of new paper, paper books did not completely replace bamboo slips and silk books. The reason is either insufficient production or people's ideas have not changed. With the development of social economy and culture, people fully realize the superiority of paper. Cai Lun paper has also created favorable conditions for the circulation of books through copying. Because paper is easier to copy, words and books are more widely spread.
Jin Shu? Wen Yuan? Biography of Zuo Si: "Therefore, the government struggles to write, and Luoyang is precious for it." "Biography" mentioned in the allusion of "Luoyang paper is expensive" is another important way of book circulation in Han Dynasty.