Zhang Yan-Yuan’s Fa Shu Yao Lu(法书要录) written in the Tang dynasty, is an important compilation of calligraphic theory from the Tang dynasty and before. With his own insight and vision in the art of calligraphy, as well as his rich family collection and other unique natural conditions, the editor, with a heart to pass on traditional culture and art, took the essence from the vast literature, extracted the essence of it, and worked tirelessly to compile it into a huge volume. The editor does not say a word in the book, but through the selection and abandonment of the content, the order in which the content is presented, the book is logically clear, right and wrong, regardless of its own position and viewpoint. From the overall viewpoint of the book, the content emphasises art over technique; highlights its heritage and historicity from a cultural perspective; establishes the authentic status of Two wangs by declaring the banner; collates, catalogues, examines, discerns forgeries, criticises, authenticates, legends, and narrates different perspectives and aspects of the art of calligraphy by adopting different styles of writing at large; while focusing on a comprehensive system of information from eight dimensions, with clear priorities, prominent views, and The book also focuses on a comprehensive and systematic approach to the material in eight dimensions, with a clear distinction between major and minor points of view, either narrating or discussing, or writing or editing, showing in three dimensions the profoundness of ancient Chinese calligraphic theory and the orthodox calligraphic thought of respecting Two wangs. Secondly, the book also has a positive historical value in terms of preserving valuable documents, deconstructing historical documents to preserve their authenticity, promoting the orthodox status of Two wangs calligraphy, and establishing a paradigm of compilation style for future generations. Of course, Zhang Yan-Yuan could not have done it all on his own, and there are regrets in the choice of titles and unsatisfactory classification of documents in Fa Shu Yao Lu(法书要录), but the flaws do not obscure the merits, and his theoretical contributions to calligraphy are indelible.