① The northern line starts from Chang 'an, runs along Weihe River to Guo County (now Baoji), crosses Zhangxian County (now Longxian County), crosses Liupanshan Guyuan and Haiyuan, runs along Zuli River and crosses Jingyuan Yellow River to Guzang (now Wuwei), which is an early route with short journey and poor supply conditions along the way.
② The southern line starts from Chang 'an, along the Weihe River, passes through Longguan, Shangguan (now water), Didao (now Lintao) and Bao Han (now Linxia), from Yongjing to the Yellow River, passes through Xining, and the bigger the bucket, the bigger the valley (now partial ferry) to Zhangye.
(3) The central line and the southern line separate in Gao Shan, cross Longshan, reach Jincheng County (now Lanzhou), cross the Yellow River, return to Zhuanglang River, and turn Wushaoling to Guzang. Although the southern line has good supply conditions, the detour is long, so the central line later became the main line.
After the North-South Central Line meets, it goes from Zhangye to Dunhuang via Jiuquan and Guazhou. The middle part. Dunhuang to Congling (now Pamir) or Zhuluo (now Chambul).
There are two routes from Yumenguan and Yangguan to the Western Regions: from Shanshan, north of Nanshan and west of Bohe, to South Road in shache, and from South Road to west of Congling, there is a big moon home, which has rested in peace. From Wang Ting (now Turpan) to Qianche Division, take Beishan and Bohe West to Shule (now Kashgar) as the north road. If the road in the north crosses the Green Ridge in the west, it will lead to Dawan, Kangju and Chae Yeon (between the Black Sea and Aral Sea). There are two important forks in the north road: one is the south road from the southwest of Yanqi, crossing the Taklimakan desert to Yutian; First, from Kuqa (now Kuqa) westbound via Gu Mo (Aksu) and Wensu (Wushi), over Daling (Bieliguan), via Chikou City (the capital of Wusun), westbound to Virote.