Pettersen was even for the day through 12 holes and tied with Azahara Munoz for first before putting the tournament away with three birdies in the final six holes of the tournament.
She ended up at 9-under-par 279 and collected $300,000 with the win. Munoz finished with a final-round 70 that left her in second, five strokes behind Pettersen. Caroline Hedwall was third at 2-under and Ji Eun-hee took fourth at 1-under for the tournament. Hedwall and Ji also turned in 2-under 70s Sunday.
Pettersen, who led after each round, had a second-hole birdie that pushed her lead to five strokes but bogeys at Nos. 4 and 9 along with a birdie at the par-4 seventh had her make the turn even.
Munoz made up ground with a birdie at No. 4 and then two more at 7 and 8. Another at the 12th pulled her even with Pettersen at 6-under. But Munoz had a bogey at 13 while Pettersen posted back-to-back birdies at 13 and 14.
Munoz dropped another stroke at 16 to fall four strokes back and Pettersen capped the with an 18th-hole birdie.
It was the 14th LPGA title of Pettersen's career, three of which have come since Sept. 1. She's won six times -- twice in Taiwan -- since Oct. 21, 2012.