The references of traffic papers in the Tang Dynasty include these contents: Bai Shouyi's Traffic History of China (Business1936; Henan People 1987 reprint), Tao Xisheng, Ju Qingyuan, editor-in-chief of Traffic in the Tang Dynasty (China Economic Historical Materials Series, the fourth part of the Tang Dynasty), National Peking University Publishing Group1937; Photocopy by Taipei Food Publishing House 1974) and Lou Zuyi's History of China Postal Development (China 1940). Among them, Traffic in Tang Dynasty, edited by Dao et al, has made great efforts in textual research of traffic historical materials, and it still has its reference value. Li Jiannong's Draft of Economic History of Wei, Jin, Southern and Northern Dynasties, Sui and Tang Dynasties (mimeographed version of History Department of National Lantian Teachers College,1943; Sanlian 1959) has devoted a section to the commercial traffic in the Tang Dynasty, which is divided into two levels: inland river traffic and maritime traffic. The former is divided into waterway transportation and post road transportation, and the canal transportation in the Tang Dynasty, the waterway between Jianghuai and Hunan, the excavation of Dayuling Road and its significance, the land and water road from Ezhou to Chang 'an, and the post road centered on Chang 'an are discussed in detail. Although the maritime traffic part relies on Sangyuan's Research on Trading Ports in Tang and Song Dynasties and Sino-Japanese Traffic History, it also puts forward its own judgment in many places. Some works on dynastic history also describe the traffic problems in the Tang Dynasty more or less. Lv Simian's History of the Sui, Tang and Five Dynasties, Chapter 19, Section 6 Traffic (Shanghai Zhonghua1957; On the basis of full possession of official historical materials, Shanghai Ancient Books l959 analyzes the traffic problems in the Sui, Tang and Five Dynasties, and discusses inland water transport and water transport, canal excavation and traffic jam, land excavation, land transportation including cars, horses and donkeys, and transportation facilities and systems including post system, horse biography, post horse, limited journey and waiting. Maritime transportation, shipbuilding and bridges are also discussed. Cen's History of Sui and Tang Dynasties (Higher Education 1957) also devoted a section to the "transportation equipment and routes" in the Tang Dynasty (see section 59), which is divided into two aspects: equipment and technology, and foreign important sea lanes. The former briefly describes the post road, waterway, shipping, customs system, navigation trade and types of seagoing ships in Tang Dynasty. The latter is the South China Sea Passage and the Northeast Passage, which is quite popular. The first volume of Wang's History of Sui, Tang and Five Dynasties (Shanghainese 1988) is devoted to the post station system and transshipment system in the Tang Dynasty, as well as the traffic routes between the Tang Dynasty and Asian countries. The former refers to the remnants of Dunhuang and Turpan documents and makes an important explanation on the problems of hotels and post stations. Although these works on dynastic history have a brief description of traffic, they are concise, comprehensive and have many original opinions, so they are still documents that should be consulted to discuss this topic.