Zhengding City Wall, built to prefecture-level standards, is magnificent in scale and exquisite in layout. It was first constructed in 352 AD during the Eastern Jin Dynasty and the Sixteen Kingdoms period, originally named "Anle Lei" (Fortress of Peace and Joy). During the Northern Zhou Dynasty, it was rebuilt as a smaller stone wall with a circumference of only 13 li. In the Tang Dynasty, Li Baochen, Military Governor of Chengde Army, expanded it into an earthen wall with a circumference of 20 li to protect the city from flooding by the Hutuo River. Successive dynasties—Song, Yuan, and Ming—carried out varying degrees of repairs and expansions. The existing wall today dates from the Ming Dynasty. It stands 3 zhang and 2 chi high, 2 zhang wide at the top, and has a circumference of 24 li. The wall has four gates: Yingxu (Greeting the Sun) in the east, Zhenyuan (Pacifying the Frontier) in the west, Changle (Lasting Joy) in the south, and Yong'an (Eternal Peace) in the north. Each gate features three defensive structures: an outer barbican, an inner barbican, and the main gate, forming a winding defensive system that is easy to defend but difficult to attack. In 2013, it was designated a Major Historical and Cultural Site Protected at the National Level by the State Council.

Zhengding South Gate, also known as Changle Gate, is one of the four gates of the ancient city and an iconic landmark of Zhengding County. In accordance with the important instructions of General Secretary Xi Jinping, the restoration of the ancient city wall was prioritized as a key project for heritage conservation. A total of 230 million yuan was invested to restore the Changle Gate tower complex and 5.2 kilometers of the ancient wall, along with high-standard lighting for 2.8 kilometers of the southern section. The restored site opened to the public on September 2, 2017. The western and northern gate ruins have also been reconstructed. The eastern gate, currently occupied by the No. 4 Mountain Military Base, has completed preliminary handover procedures, and its original appearance will be restored in the next phase.

With ongoing conservation efforts, Zhengding Ancient City has regained its historic charm. The vision of "climbing the gate towers, seeing the ancient pagodas, and recalling the nostalgia" has become a reality. At night, brilliant lights illuminate the ancient city, temples, and pagodas, creating a dreamlike, picturesque atmosphere.