Most of the biographies added in the Book of the New Tang Dynasty are based on my own chapters or the memories of later generations, collecting and sorting out inscriptions, various miscellaneous histories, notes, novels and so on. Most of the records in the new books are more detailed than those in the old ones, and the records of food and goods have also increased from the original two volumes to five volumes. The contents about opening up wasteland, harmony, minerals, vocational fields, grain, etc. are not available in Old Tang Shu. Geographical records have increased from four volumes to eight volumes, and there are many innovations in content. It records a large number of historical facts about the construction of canals and weirs all over the country, which is helpful to understand the irrigation and water conservancy in Tang Dynasty. It also recorded in detail the tribute of local products in various provinces, prefectures and counties; The military government, troops, towns and guards set up in various places are listed one by one, reflecting the military deployment in the Tang Dynasty. Focusing on Jimifu is helpful to understand the living distribution and development of various ethnic minorities in the Tang Dynasty. According to the article "Four Emperors of Hua Di" written by Prime Minister Jia Dan, this paper briefly describes seven ways of communication with overseas countries in the Tang Dynasty, which is helpful to understand the friendly communication between the Central Plains and ethnic minority areas and Asian countries in the Tang Dynasty. It is very important to supplement the works of Tang people after the middle Tang Dynasty that are missing in the Book of Classic Records of Old Tang Dynasty.
The new and old Tang books have their own advantages in preserving historical materials. The Book of the Old Tang Dynasty preserved a large number of authentic records of the Tang Dynasty and original materials of national history, while the Book of the New Tang Dynasty made extensive use of all kinds of historical materials that the Song people could see, enriching and supplementing the shortcomings of the Book of the Old Tang Dynasty. Therefore, the historical value of the two books in Tang Dynasty has its own advantages and disadvantages.