Park carded five birdies in the impressive victory -- her second major career title following a win at the 2008 U.S. Women's Open.
She closed at 15-under 273, four better than reigning Rookie of the Year So Yeon Ryu, who carded seven birdies en route to a 7-under 65.
Lizette Salas, who entered the day in second place, stumbled to a double bogey on her first hole and never recovered, turning in a final-round 79 to finish in a tie for 25th place at 2-under.
Ending knotted for third at 9-under were Caroline Hedwall (68) and Suzann Pettersen (69).
Haeji Kang (68) and Karrie Webb (72) tied for fifth at 6-under.