Hirst, who topped the list in 2005, retakes the top spot after a recent sale of his work which made £111m.
The magazine said Hirst - famous for his animals preserved in formaldehyde - “overshadowed and outshone” in an art market shaken by the credit crunch.
Mysterious graffiti artist Banksy made the the list at 63 - the first street artist to do so.
The list also includes art collectors, gallery curators and institutions active in the world of art.
Financial clout
Kathy Halbreich, an associate director of New York’s Museum of Modern Art, becomes the first woman to make the top 10 in her own right.
Russian billionaire and Chelsea FC owner Roman Abramovich also enters the list at 54 as a collector of art.
Figures from China and India’s art worlds have made progress this year, with Chinese artist Cai Guo-Qiang rising 30 places to 69.
Earlier this year, he became the first Chinese artist to stage a solo exhibition at New York’s Guggenheim museum.
Hirst’s star has risen on the list in the last two years - in 2006 he was outside the top 10, and moved up to sixth place last year.
Another well-known name, collector Charles Saatchi, has slipped from seven in 2007 to 14.
He topped the first power list, which was published in 2002.
Art figures are measured on a number of criteria including financial clout, influence on the international stage and activity in the past year. (BBC NEWS)