The Records of the Western Regions of Datang can be used as data for studying the history of which region.

The Records of the Western Regions of Datang recorded Xuanzang's personal experience and hearsay about 138 countries, regions and city-states, including Xinjiang Uygur Autonomous Region in China, Central Asia, Afghanistan, Iran, Pakistan, India, Nepal, Bangladesh and Sri Lanka. The arrangement of countries in the book is basically in the order of itinerary: from Aryan country described in Volume I to Gabon country, that is, from China and Xinjiang to Afghanistan via Russian Central Asia; The second volume is the general situation of India, which records the transition from Luanlang country to Kendra country, that is, from Afghanistan to northern India; Volume 3- 1 1 refers to countries from Ujana to Vaarala, including India in the north, middle, east, south and west, as well as hearsay countries; Volume 12 mentioned that from Cao Juguo to Najanbo's old country, that is, from Afghanistan to southern Xinjiang, China. The content of this book is very rich, describing the geographical situation, land and water transportation, climate, products, nationalities, languages, history, politics, economic life, religion, culture, customs and habits. In particular, religious temples and Buddhist stories and legends in various places are recorded in detail. Careful, well-documented, concise and fluent.