The Southern Section Road Archeological Sites includes a series of central roadway remains stretching from Zhengyangmen to Yongdingmen. As of the end of 2022, three sites have been identified. The Stone Slab Road Ruins north of Yongdingmen, located about 100 meters north of the gate, preserve remnants of stone slabs symmetrically aligned with the Central Axis, reflecting the paving and construction practices of the Outer City imperial road during the Qing Dynasty. The Historical Central Roadway Ruins inside Yongdingmen, about 400 meters north of the gate, reveal how the central roadway was used across different historical periods since the Ming Dynasty. The Zhushikou South Drainage Ditch Ruins, located roughly 5 meters south of the Zhushikou Church, show the position and structure of the brick-lined drainage ditches flanking the Qing Dynasty central roadway.
The Southern Section Road already existed in 1420. The road from the Tianqiao Bridge (Celestial Bridge) to the Yongdingmen Gate was repaved with stone in 1729. In 1791, an earthen road of two zhang (traditional Chinese length unit, one zhang is around 0.3 meters) wide was added to the sides of the imperial road. The board-covered ditches flanking the stone-paved roadway were successively reconstructed with bricks. Six more ditches were built, flanking the stone-paved central passageway greatly changing the landscape of the section between the Tianqiao Bridge and the Yongdingmen Gate. The Jiaqing Emperor had the ditches infilled, claiming that they had damaged the fengshui in 1813. The road remains and Qing dynasty slabs were rediscovered in 2004. In 2022, archaeologists further discovered the Road Foundation Site North of the Yongdingmen Gate and the Drainage Ditch Site South of Zhushikou.
The southern section of central axis road was the passage-way for emperors to go to the southern suburbs for sacrificial ceremonies. The remains of the road indicate that the central roads in that section of Beijing Central Axis were used from the Jiajing reign of the Ming dynasty and continuously maintained and reconstructed at different periods of history. They are the tangible carriers of the routes of imperial ceremonial and ritual activities during the Ming and Qing dynasties.
The southern section of central axis road consist of two roadways paved with granite slabs. The pavement of the slabs on both sides are the same, using stripe-shape granite that match the records in the historical documentation of the Qing dynasty.
The southern section of central axis road has the remains of seven sets of roads stacked upon one an-other (L1-L7). These can be divided into the following categories based on the construction time: before 1729 (L7); between 1729 and the Republican period (L6); the Republican period (L5); and modern times (L1-L4).
The exposed part of the Drainage Ditch Site South of Zhushikou is laid with blue-gray bricks, with the top covered with stone slabs, and the bottom paved with bricks. Beneath the bricks are pegs, showing the engineering techniques in constructing drainages on the side of the central road that was functional during the Qing dynasty.
中轴线南段道路遗址包括从正阳门至永定门的一系列中央道路遗迹，截至2022年底已发现三处。永定门北侧石板道遗址位于永定门北100米处，残存的石板与北京中轴线大致对称，展现了清代外城御道的铺设和营建情况。永定门内中轴历史道路遗址位于永定门北约400米处，展现了明代以来不同历史时期中央道路的使用情况。珠市口南排水沟遗址位于珠市口教堂南约5米处，展现了清代中央道路两侧砖砌排水沟的位置和结构。
中轴线南段道路早在1420年便已存在。天桥至永定门的道路于1729年重新铺设石板。1791年，在御道两侧增设了宽二丈的土路。石板路两侧的木板沟，也陆续改建为砖块。在石板中央通道两侧，又增建了六条沟，大大改变了天桥至永定门一带的面貌。嘉庆帝于1813年以破坏风水为由，下令填埋这些沟渠。2004年，道路遗迹及清代石板被重新发现。2022年，考古学家又发现了永定门北侧的道路基址和珠市口南侧的排水沟遗址。
中轴线南段道路是皇帝前往南郊举行祭祀仪式的通道。该段道路遗存表明，北京中轴线南段的中心道路自明嘉靖年间开始使用，并在不同历史时期不断维护和重建，是明清两代皇家礼仪活动路线的有形载体。
中轴线南段道路遗址由两条花岗岩石板铺就的路面组成。两侧石板的铺装方式相同，均为条状花岗岩，与清代史料记载相符。
中轴线南段道路遗址现存七组叠置的道路遗迹（L1-L7）。这些道路遗迹按建造年代可分为：1729年以前（L7）；1729年至民国时期（L6）；民国时期（L5）；近代（L1-L4）。
珠市口南侧排水沟遗址的出露部分铺设青灰色砖块，顶部覆以石板，底部铺以砖块。砖下有木桩，体现了清代在中央道路一侧修建排水沟渠的工程技术。
