"On Calligraphy" was an essay written by Han Yu, a famous ideologist, politician, and cultural critic in the Tang Dynasty. It mainly discussed the importance of reading and the significance of reading to individuals and society. Han Yu believed that reading was not only to obtain knowledge, but also to improve his own quality and thinking ability. Only by reading excellent books could one continue to learn and improve to become a better person. Reading was very beneficial to both individuals and society. Through reading books, people could gain all kinds of knowledge and experience to enrich their horizons and ways of thinking. At the same time, reading can also promote people's communication and expand social circles to enhance interpersonal skills. In On Calligraphy, Han Yu also emphasized the uniqueness and variety of reading. He believed that everyone should choose books that they were interested in to find their own pleasure and value in reading. At the same time, he also believed that reading should be inclusive and not be rejected because some books were not suitable for him. Calligraphy Theory was a philosophical and enlightening article. It had important guiding significance for people on how to improve their reading level and quality and how to better adapt to the development of society.