Dame Helen Mirren was crowned queen of Venice, for her portrayal of Queen Elizabeth II in The Queen.
She won a best acting gong for the film, which is a fictionalised account of the week following the death of Princess Diana.
The award came as a consolation prize for her director Stephen Frears, whose picture was pipped to the top award by Chinese film Still Life.
Jia Zhang-ke follows in the footsteps of fellow Asian director Ang Lee, whose Brokeback Mountain snagged the Golden Lion last year.
His film tells the story of people returning to a village devastated as a result of the Three Gorges project, which has seen more than a million Chinese relocated from their homes to make way for a dam.
Accepting her award, Helen Mirren, 61, said: "It's an incredible honour to have this film take its first steps here at the Venice Film Festival."
After the ceremony French star Catherine Deneuve, who headed the jury for the best picture award, praised the "beauty of the cinematography and the quality of the story without getting political" in Still Life.
Other winners included Ben Affleck for his role in Hollywoodland, a dramatisation of an investigation into the death of Adventures of Superman TV star George Reeves.
Spike Lee's film When The Levees Broke: A Requiem in Four Acts was named best documentary, while Alfonso Cuaron's Children Of Men won a prize for its director of photography Emmanuel Lubezki.
Brit Daniel Elliot also scooped an award for his short film The Making Of Parts.
