Pettersen birdied the first three holes at the Ko Olina Golf Club and then held off a challenge from Hee Kyung Seo to finish 54 holes at 14-under 202. Seo bogeyed the final hole to finish at 203 following a round of 66.
Defending champion Ai Miyazato was alone in third at 205 and Hyo Joo Kim was another shot back.
Stacy Lewis, trying to regain the world's No. 1 ranking, was tied for fifth at 207 with Lizette Salas and first-round leader Ariya Jutanugarn.