Foreign leaders at the opening ceremony, include Pakistan President Asif Ali Zardari, Kyrgyz President Roza Otunbayeva, Azerbaijan`s Vice Premier Abid Sharifov, and Kazakhstan`s Deputy Prime Minister Aset Isekeshev.
Vice Premier Li is expected to succeed Premier Wen Jiabao in 2013.
Organizers of the event said about 50,000 officials and businessmen from China and about 30 other countries, regions and international organizations are expected to attend the five-day trade fair.
Officials have said police have thwarted several attempts to sabotage public safety in the run-up to a state-level international trade fair by the suspected East Turkistan Islamic Movement, fighting for separation from the region.
The last attack was towards end of July during which 22 people were killed in attacks at Kashghar city in the province.
China subsequently said the militants were trained in Pakistan terror camps.
Zhu Hailun, the top official of Urumqi in Xinjiang Uygur Autonomous Region, told media ahead of the opening of China-Eurasia Expo, that separatists, religious extremists and terrorists have been plotting to sabotage the expo.
He confirmed that airport security staff in Urumqi on August 7 arrested a man who attempted to take a knife on board.
He has been detained on the suspicion of planning to carry out an attack during the flight.
"There have been many similar cases of attacks being blocked by police," Zhu said. "Hopefully we have intervened in time to nib the violence in the bud," he said.