Chang 'an is at the center of Chinese territory, which was beneficial to the imperial system when it was compared with feudal system in ancient times. And there is the Yellow River beside it. The ancient capital is more important to the water source.

The historical capital of the unified state or local government in China. Also known as capital, capital, capital, capital. Kyoto is not only the political center of a dynasty, but also its economic and cultural center. So its setting should be relatively stable. However, with the development of national politics and economy and the need of expanding the situation, Kyoto often moves from the old capital to a more suitable new capital. In the history of China, not only have many regimes experienced the gradual shift of Kyoto status in their own development, but on the whole, the status of Kyoto in past dynasties has also shown the shift mainly from east to west and then from north to south.

The relocation of Kyoto must also consider various geographical factors: ① Kyoto should be built in an economically developed and wealthy area to maintain the material needs of the ruling group; (2) Kyoto should be located in the central part of the country, or have convenient traffic conditions, so as to facilitate the implementation of government decrees and control internal and external affairs; (3) Kyoto should choose natural conditions where risks can be defended, so that it will not be destroyed by external forces and the country will have long-term stability. The location of the capital of any political power in history can not fully meet the above three conditions, and it can only choose a relatively favorable location according to the main contradictions at that time, so the choice of the capital often reflects the general situation of that period. On the other hand, once the capital is determined, it will also have a certain impact on the political, military and economic development of the whole country.