Baodai bridge is a famous scenic spot in Suzhou, Jiangsu Province. It is also called the Dragon Bridge, and together with Zhao Zhouqiao and Lugou Bridge, it is called the top ten famous bridges in China.

It spans the Yaya River between the ancient canal and Dan Tai Lake, 3 kilometers away from Suzhou. Built in the 11th to 14th years of Tang Yuanhe, it is a famous porous stone arch bridge at home and abroad.

Its construction is closely related to the water transportation in the history of China. As we all know, the areas along the Yangtze River and Zhejiang Province have been the land of plenty since ancient times, and emperors of all dynasties used it as an important place to gather wealth and endow them with wealth. During the Great Cause years, Yang Di dug the Grand Canal in the south of the Yangtze River and shipped grain and treasures from Jiangsu and Zhejiang to Kyoto. In the Tang Dynasty, water transportation was unprecedentedly busy. However, a waterwheel loaded with imperial grain from Suzhou to Jiaxing is hard to catch on in the northwest in autumn and winter. However, there is a gap about 300 meters wide at the junction of Dan Tai Lake and the canal, which needs to be filled as a dike; However, this will cut off the passage from the lake to the sea through Wusong River, and the dam will be washed away by water. Therefore, Wang Zhongshu, the secretariat of Suzhou, decided to build a bridge lake and donate his own jade belt to fill the bridge, hence the name of baodai bridge.

Baodai bridge bridge deck is wide and flat, consisting of 53 holes, with a length of 249.8 meters. The total length is 3 17m and the width is 4.1m. The bridge is trumpet-shaped with a lower end width of 6. 1 m. There are a pair of mighty green stone lions at each end of the bridge, and there are four stone pavilions and five-level octagonal stone pagodas at the northern end. The whole baodai bridge is long and narrow, riddled with holes, reflected in the water, reflecting the actual situation, just like a black dragon floating, but also like a towering back; It not only provides convenience for pedestrians, but also adds a beautiful scenery to the Jiangnan water town. In engineering technology, it uses flexible piers, which can prevent multiple bridge holes from collapsing. Its arch construction method adopts "multi-twisted arch", which is extremely rare in the history of ancient bridge construction.

The monk in the Yuan Dynasty kindly described it as: "I borrowed his stone, but kept it as a beam. Go straight from the embankment and cross the center of the water. Egrets fall in autumn and black dragons float in the sunset. The sound of the waves began that night and merged into a list. " It can be seen that in the Yuan Dynasty, it was not only a large-scale stone arch bridge, but also a busy transportation task.