Starting from the central point of Yongdingmen, which was demolished, it passes through Zhengyangmen, Tiananmen, Wumen, Taihe Hall, Zhonghe Hall, Baohe Hall, Ganqing Palace, Kunning Palace, Shenwumen, Wanchun Pavilion, Shouhuang Hall and Drum Tower in the south, and finally reaches the central point of the bell tower, with a total length of 7.86 kilometers. This central axis connects four cities in series, namely the outer city, the inner city, the imperial city and the Forbidden City.

Beijing city is centered on this central axis, forming a pattern of east-west symmetry, which is reflected in the place names.

The clear central axis of Beijing started in the Jin Dynasty, and an imperial road runs through Fengyimen in the outer city, Xuanyangmen in the imperial city and yingtianmen in Miyagi, but there are no famous buildings on the imperial road. In the Yuan Dynasty, the central axis was formally formed, located at the center line of the old Gulou Street and its extension line to the south, crossing the center of Miyagi on the east bank of Taiye Pool (now Beihai and Zhongnanhai) and reaching the main entrance of the outer city. In the Ming Dynasty, the rulers moved the central axis of Beijing to the east by 15 meters, which finally formed the current pattern. The purpose was to highlight the palace, not to be connected with the Xiyuan Taiye Pool, to avoid the numerous pavilions on Qionghua Island and Xihaizi, and to have corresponding space in the middle, which made the palace look dignified and rich. Therefore, the central axis of Beijing is not entirely on the center line of the city. For example, the distance between Zhengyangmen and Chongwenmen is nearly 2 meters than that between Xuanwumen.

The purpose of establishing the central axis is to emphasize the central position of feudal emperors, just as China was named China, which means "the central country of the world". The overall layout of the city is centered on the central axis, with the ancestral temple on the left and the social altar on the right; The imperial court is in front, and the market is behind, that is, "Zuo Zu You She" and "Qian Chao Hou Ye", so Beijing has become one of the most brilliant cities in the world in terms of urban layout.

In order to reflect the central position of the feudal dynasty in the country, many famous buildings in Beijing are located on the central axis, such as Zhengyangmen, Tiananmen Square, the Forbidden City, where emperors live, the central clock for telling the time in the whole city, and the Drum Tower. These buildings are symbols of both the ancient capital Beijing and China civilization, and occupy a high position in the history of world civilization. Therefore, there is no one who comes to Beijing to visit.

After the founding of New China, Tiananmen Square, Monument to People's Heroes, Chairman Mao's Memorial Hall and so on were successively expanded. People who have been to Beijing may be interested in many place names in Beijing: Dongzhimen and Xizhimen; There are East Four and West Four; There are Dongdan and Xidan; There are Dongbianmen and Xibianmen; There is a left door and a right door ... What's going on?

It turns out that Beijing has two famous central axes, and the other is Chang 'an Street.

Chang' an Street is well-known at home and abroad, and it is known as "the first street in China". Chang 'an Street, built in the Ming Dynasty, is the main road for the construction of the Forbidden City, the Imperial City and the inner and outer cities in Beijing. According to relevant records, it was built at the same time as the Imperial City from the fourth year to the eighteenth year of Yongle in the Ming Dynasty (146-142), which is one of the important parts of the overall planning for the construction of Beijing City in the Ming Dynasty, with a history of 6 years. Chang 'an Street, named after the left and right gates of Chang 'an on both sides of Tiananmen Square. After the founding of New China, in order to solve the traffic problem of Chang 'an Avenue, the left and right doors of Chang 'an were demolished in August 1952.