The architecture in Ming and Qing dynasties emphasized the direct combination of beams, columns and purlins, and reduced the role of bucket arch as an intermediate level. This not only simplifies the structure, but also saves a lot of wood, thus achieving the effect of obtaining more building space with less materials. Masonry was also widely used in Ming and Qing dynasties, which promoted the development of masonry structure. During this period, the common beamless hall in China is the concrete embodiment of this progress. In a word, the architectural art of Ming and Qing dynasties did not go downhill blindly, but it was like a fading sunset on the horizon, still shining.
During the Ming and Qing Dynasties, the number of cities increased rapidly and the urban structure became more and more complicated. Due to various handicrafts, commerce, foreign trade, military strongholds and transportation hubs, various towns and villages such as Jingdezhen, Yangzhou, Ahava and Xiamen have sprung up all over the country. At this time, brick cities, moats, provincial capitals, prefectures and counties were built in all cities, each with its own rules. The existing well-preserved city wall is Ming Xi An. It was built in the third to eleventh year of Hongwu in the Ming Dynasty (1370- 1378), and was expanded on the basis of Chang 'an Imperial City in the Tang Dynasty. It was built with bricks in Qin Long in the fourth year of Ming Dynasty (1570) and has been preserved to this day. The west and south walls of Xi 'an City in Ming Dynasty were basically the same as those of Chang 'an Imperial City in Tang Dynasty, and the east and north walls expanded outward by about one third. The wall is 12m high, 12- 14m wide at the top and 15m wide at the bottom. The city is rectangular. The south wall is 4255 meters long, the north wall is 4262 meters long, the east wall is 1886 meters long, and the west wall is 2708 meters long, with a circumference of about 13.7 kilometers. There are gates on all sides of the city, and the tower of each gate has three floors: the tower is outside, the arrow tower is in the middle, and the main building is at the innermost, which is the main entrance of the city. The watchtower and the main building are connected by fences to form an urn. Build a turret at every corner of the city wall. There are 98 enemy platforms (horse faces and piers) on the city wall every 120 meters, and enemy towers are built on the platforms for soldiers to shelter from the wind and rain and store materials. There are 5,984 spies (battlements) on the outside of the top of the city wall, with battlements and mouths for archery and lookout, and a female wall without battlements on the inside to prevent pedestrians from falling. There is a moat around the city. The whole city wall is magnificent, forming a scientific and rigorous defense system of the ancient castle.