Azarenka broke Sharapova three times - with one break back - in the opening set as the Russian served six double faults.
The world number two improved her service in the second set but won only 14 per cent of points on her second serve.
"I'm really happy to finally have a really good result here - I've been coming here for the last four years and I'm happy I could finally show my game and hold the trophy," Azarenka said.
"I've worked so hard and it all came together here," added the Belarussian who last won a title in Indian Wells in March.
Azarenka, who had beaten world number two Sharapova in their previous five hardcourt meetings, completely outclassed the Russian in Beijing's National Tennis Stadium.
"Victoria played an amazing match today," said Sharapova, who hit 39 unforced errors. "There's a reason she's number one in the world right now."
Sharapova has not won a WTA title since claiming the French Open in June while Australian Open champion Azarenka's most recent triumph came at Indian Wells.
However Azarenka has won five titles in all this year while Sharapova has three to her name.
Azarenka has now beaten Sharapova four times in five meetings in 2012, including victories in the Grand Slam final in Melbourne and the semi-finals of the US Open.