The Suxi-Changnan Expressway starts from the Changhuang former Huanghu junction, crosses the Xiyi Expressway, passes through the south of Xueyan Town, enters the territory of Wuxi Mashan, passes east through Taihu Lake, passes through Nanquan, and ends at the Nanquan Junction and Wuxi Ring Taihu Highway Connect. The longest and widest underwater tunnel in Suxi-Changnan Expressway is the longest and largest highway infrastructure construction project in the province so far. Suxi-Changnan Expressway is in the planning of the “five vertical, nine horizontal and five joint” expressway network in Jiangsu Province The "Hengliu" component, and the Taihu Tunnel is the key control project of the Suxi-Changnan Expressway Project. The Taihu Tunnel has a total length of 10.79 kilometers. The cross section adopts a folded plate arch with two holes and a pipe corridor. The net width of the hole is 17.45 meters, the net height is 7.25 meters, and the length and width exceed the Hong Kong-Zhuhai-Macao Bridge undersea tunnel. It is the longest and widest underwater tunnel in China.