The Xi'an Ancient City Wall was built from 1370 to 1378 AD under the order of the first emperor of Ming Dynasty (Zhu Yuanzhang 朱元璋). Long before the establishment of Ming Dynasty, Zhu Yuanzhang took an advice from a recluse to build up high walls, hoard abundant food supplies and take time to claim the throne. After he united the country and established Ming Dynasty, he started to build city walls all over the country. Xi'an Ancient City Wall was built at this time. Xi'an was once the capital city of Tang Dynasty (618 - 907 AD), once called Chang An (长安) at that time. The Ancient City Wall built in Ming Dynasty was constructed and enlarged on the foundation of imperial city wall of Tang Dynasty.
Now, Xi'an Ancient City Wall is the largest and best preserved existing ancient city wall in China. Xi'an Ancient City Wall embodied the defense function perfectly. The rectangular city wall is 13.75km in length (about 4 hours walk), 12m in height, 12 – 14m in thickness at the top and 15 – 18m in thickness at the base.