Chang 'an City in the Tang Dynasty and the night market that appeared later pointed out the development characteristics of ancient cities in China.

1, from focusing on politics and military to focusing on economy. From the pre-Qin Dynasty to the Tang Dynasty, towns were established in military towns and eventually developed into cities. Later, with the economic development, trade prosperity and frequent exchanges, military and political functions began to change to economic functions. Such as the capital of song dynasty and Kaifeng.

2. Large trade fairs can be turned into cities, such as Hohhot.

3. Large-scale production areas can also become cities, such as Jingdezhen.

4. In space, the night market appeared, which broke the time limit, while shops could be opened outside the original city, which broke the space limit.

5. Change from functionality to practicality. For example, the streets of the imperial city are very wide. In the early years of Sui Dynasty, the width of Daxing (Chang 'an) street could reach120m. But it is not practical, and it is difficult for ordinary people to cross the road. So residents cultivated land on both sides of the road to seize the official road. Therefore, when Luoyang, the eastern capital, was built, he no longer designed wide and impractical roads, but paid more attention to practicality, not just highlighting royal majesty.