During the Shang Dynasty in China, people carved characters on the scapula of tortoise shells, cattle, sheep, pigs and other animals one by one. Subsequently, people wrote articles with wood chips (also known as bamboo slips) and bamboo pieces (also known as slips) with one-to-one specifications; We will also use silk as paper to write in the future. During the Eastern Han Dynasty, with the development of economy and culture, bamboo and silk became more and more unsuitable for writing. In order to make an ideal writing material, Cai Lun made a light and economical paper with bark, hemp, rags and waste fishing nets as raw materials on the basis of using waste silk cotton to make paper, and summarized a set of relatively perfect papermaking methods, which made the papermaking technology leap. In A.D. 105 (in the reign of Liu Zhaonian in the first year of Han Yuan Xing), Cai Lun presented the finished paper to the court and was praised by the emperor. From then on, people began to use this kind of paper, and the paper made in Cai Lun was called "Cai Hou Paper" all over the country.