Hangzhou Bay Sea-crossing Bridge is a convenient passage for the artery line of Tongsan State Highway to go across Hangzhou Bay. The bridge lies in the Yangtze Delta, an area with most plenty vigor in implementation of reform and open policy and developed economy in China. The bridge starts from Zhengjiadai in Haiyan, Jiaxing City in the north and extends to Andong in Cixi, Ningbo City in the south. With a full length of 36km, it is presently the longest sea-crossing bride in the world.

The bridge is designed into bi-directional six-lane expressway with adoption of new process and new technology with high content of application of integral erection of large prefabricated structure, such as integral cast-in-place of model frame and cantilevered assembly for suspended arm of steel box girder.