The bridge provides a vital link between booming provinces in China's most dynamic economic zones on the eastern seaboard - an area that accounts for about 20 per cent of the country's GDP.
Wang Yong, vice mayor of Ningbo, said the bridge's "design, construction, facilities, management and other various aspects" were incomparable.
"For the bridge to be able to cross Hangzhou Bay, it is a great and difficult challenge for its construction."
Private firms provided about 29 per cent of the construction cost, making it one of China's first big infrastructure ventures to involve major private participation, according to Xinhua news agency.
The spillover from the bridge project is the Hangzhou Bay New Economic Zone which was established in June 2005, and home to more than 200 companies.
Cost $1.5 bn to build,
29 per cent borne by private sector
Spans 36km across the East China Sea
Operational in June 2008
Reduces travel between Shanghai and major port city by 120km
The zone will feature various tax incentives including tax exemption for import of machinery used in production as well as for imported goods which are exported after processing.
Shen Dingkang, president of motorcycle maker China Konced Group, said the new bridge will greatly reduce cost and speed up delivery of the machines.
"For a motorcycle maker like us, we need to deliver our products via road vehicles," he said.
"This is especially so for us as we need to send our bikes to central and northern China, and we need to pass through Shanghai and Jiangsu province."
The Hangzhou Bay bridge however is shorter than the 38.2-kilometre Lake Pontchartrain Causeway which spans a freshwater lake in southern US, often described as the world's longest.