"That all stands witness to the endlessly renewed vitality of Sino-African friendship, to the scale of the potential for co-operation and the excellent outlook for the new kind of Sino-African strategic partnership," Xi said at Beijing's Great Hall of the People.
Xi did not give an exact total.
But China-Africa trade has boomed in line with the Asian country's rise to become the world's second-biggest economy, which has been accompanied by a thirst for African natural resources to help fuel its growth.
Underscoring the continent's importance, Xi visited Tanzania, South Africa and the Republic of Congo as part of his first overseas tour after he become president in March last year.
But China's growing role has also sparked tensions in some countries.
In February last year, for example, the Zambian government seized control of a Chinese-owned coal company due to poor compliance with safety and environmental standards, its mines minister said. In 2012 workers at the mine killed a Chinese manager during rioting over work conditions.
Acclaimed primatologist Jane Goodall told AFP in a recent interview that China was exploiting Africa's resources just as European colonisers did, with disastrous effects for the environment.