Vice President Xi Jinping has already visited Jamaica, Mexico and Colombia
Chinese Vice President Xi Jinping is due in Venezuela as part of a visit to boost Chinese ties in the region.
Mr Xi is expected to sign agreements including joint ventures with Venezuela's state oil company, PDVSA, the Venezuelan foreign ministry said.
China is also set to inject $4bn (£2.8bn) into a joint investment fund that was set up in 2007 with $6bn.
Mr Xi and Vice Premier Hui Liangyu are both touring Latin America - a sign of the region's importance to Beijing.
Mr Xi would be signing accords on joint ventures for "the exploration, exploitation, processing, refining and transportation of crude oil," a Venezuelan foreign ministry statement said.
"Today we have a long-term strategic alliance for the next 100 years for the joint production of oil," Venezuelan Foreign Minister Nicolas Maduro said.
The two sides are also expected to formalise an increase in a joint investment fund set up in 2007 with initial capital of $4bn from China and $2bn from Venezuela, with Beijing now injecting a further $4bn.
"This fund will provide Venezuela with sources of financing for development projects and to maintain economic growth for the next two or three years, amid the global crisis," Mr Maduro said.
Mr Xi has visited Jamaica, Mexico and Colombia, and is due to travel on to Brazil, while Vice Premier Hui Liangyu's itinerary includes Argentina, Ecuador, Barbados and the Bahamas.
It is rare for two of China's top leaders to descend on the region almost at the same time, and indicates China's ongoing efforts to strengthen ties with and develop its influence on Latin America and the Caribbean, says BBC China analyst Shirong Chen.
China's export markets in Europe and North America have shrunk substantially in the global financial crisis, so Beijing is desperate to open up and maintain markets in Latin America.
Beijing published its first ever policy document on the region last November before President Hu Jintao visited Costa Rica, Cuba and Peru.