At the time when Zhu Yuanzhang the first emperor of Ming Dynasty (from 1370 A.D.- 1375 A.D)captured Huizhou, he was admonished by a hermit named Zhu Sheng, who told him to "built high walls, store abundant provisions and take your time in proclaiming yourself emperor", advice which Zhu Yuanzhang heeded. After the whole country was unified, he odered the local governments to build city walls on a large scale. Zhu assumed that "out of all the mountains and rivers in the world, the central Qin is the most strongly fortified and strategically impregnable." The city wall of Xi'an is an extension of the old Tang Dynasty structure, as a result of this wall building campaign.

The wall was built of earth, rammed layer upon layer during the early time. The base layer was made of earth, quick lime, and glutinous rice extract, tempered together. This made the wall extremely strong and firm. Later, the wall was totally enclosed with bricks.

Xi'an's city wall after its enlargement in the Ming Dynasty stands 12 meters high. It is 12-14 meters across the top, 15-18 meters thick at bottom and 13.7 kilometers in length. There is a rampart every 120 meters. The ramparts are towers that extend out from the main wall, the top of the rampart being at the same level as the top of the wall. The ramparts were built to allow soldiers to observed enemies who would attempt to climb the wall. The distance between two ramparts is just within the range of arrow shot from either side. This is for having soldiers to protect the entire wall without exposing themselves to the enemy. There are altogether 98 of them on the wall; each has a sentry building on top of it. The weapons in ancient times were primitive. The gates of the city wall were the strategic points in the respect that they are the only ways to go into and out of town. A watch tower is located on each of the four corners of the wall.

After several restorations, the longest unbroken section froms the Western Gate to the East Gate, a distance of approximately 5 kilometers (3 miles). Cycling on top of the wall in this section, you will have a bird's eye view of the city,