The top-seeded Dane needed only 67 minutes against the 24th-ranked Italian.
Wozniacki won 76 percent of points on her first serve -- compared to just 43 percent for Vinci -- and also saved all six break points against her at the hard-court Koza World of Sport Complex.
"I served well and pushed her around the court," said Wozniacki, who won all seven of her service games.
Vinci was broken five times in the match and lost her last three service games.
The two players are 2-2 in head-to-heads with Vinci beating Wozniacki when she was the top-ranked player in 2011.
The 24-year-old Wozniacki -- runner-up at the 2009 U.S. Open to Kim Clijsters -- has won at least one WTA title every year since 2008.
Now ranked 15th, her victory in Istanbul came just hours before golfer Rory McIlroy won the British Open by two strokes at Royal Liverpool.
After getting engaged to Wozniacki on New Year's Eve, McIlroy broke off the engagement in May with a telephone call. About a week after, Wozniacki exited the French Open in the first round.
Wozniacki Captures Istanbul Cup
ESPN.com senior writer Howard Bryant discusses Caroline Wozniacki's rout of Roberta Vinci to win the Istanbul Cup and what it means for her going forward.