China is the biggest and one of the fastest growing car markets in the world.
Geely says it has already secured financing for the deal and is keen to keep Volvo in operation.
The Chinese firm said that the deal, which Ford initially agreed to in December, included agreements on intellectual property rights as well as supply and research and development arrangements between Volvo, Geely and Ford.
"Today I am reassuring that Geely is determined to protect and nurture everything that is great about Volvo"
Geely Holding chairman
Lewis Booth, Ford's chief financial officer, said his company got a "fair price and were "very happy with the deal".
But the deal initially caused consternation among unions at Volvo, which employs around 22,000 people worldwide, including 16,000 in Sweden.
Unions opposed the deal on grounds that it was vague on expansion plans and possible layoffs.
Geely tried to ally those fears, saying that it would keep Volvo plants in Sweden and Belgium and was considering opening factories in China for the local market.
"Today I am reassuring that Geely is determined to protect and nurture everything that is great about Volvo. Volvo is Volvo and Geely is Geely," Li said.
"Volvo will be run by Volvo management, and be strategically independent. They are distinct companies. Volvo is a Swedish business with a strong Scandinavian heritage."
The Geely group has grown into one of China's largest private car makers since it launched its car manufacturing business in 1997.
It operates six car assembly and power-train manufacturing plants across China with a combined production capacity of 300,000 cars per year.
The company also owns nearly 500 dealerships and 600 service stations in the country.
Geely has an overseas sales and service network of nearly 300 outlets and runs plants in several foreign countries, including Ukraine, Russia and Indonesia.