It is the longest one among five island-mainland bridges of Zhoushan, which is the fourth longest cross-sea bridge in China after the construction of Qingdao Jiaozhou Bay Bridge, Hangzhou Bay Bridge and Donghai Bridge. The major bridge, as long as 21.020km, was constructed under complicated meteorological, hydrologic, topographical, and geological conditions. The main navigation span is 620m, which is a cable-stayed bridge with steel box girders and five spans. The other parts are installed by erecting span by single lift or bracket, cast-in-place cantilever method and prestressed on-site casting of continuous concrete structure by mobile mould. The lower-deck mainly adopted steel pipe piles, cast-in-site bored piles, cast-in-situ piers and precast piers. BRDI undertook the design for 15.7km of the bridge.