Tthe Norwegian claiming a five-shot lead after the second round in Taoyuan.
Defending champion Pettersen was three clear of the field after an opening 68 in tough scoring conditions and extended her advantage with a 69 that included an ace on the second from 133 yards.
Solheim Cup star Pettersen also birdied the ninth to be out in 33 and recovered from her only bogey of the day on the 14th with a birdie on the last.
Spain's Carlota Ciganda and South Korea's Yoo Sun-young-are Pettersen's nearest challengers on two under, Yoo's 69 meaning she and Pettersen were the only players to break 70.
Ciganda carded five birdies in her 70, but also bogeyed the 11th and ran up a double-bogey seven on the par-five 13th.
Australia's Katherine Hull-Kirk and Spain's Beatriz Recari were the only other players under par after rounds of 70 and 71 respectively.
Speaking about her hole-in-one, Pettersen said: "I called the shot, I hit it exactly how I wanted and was fortunate enough that I had a good break. It was a very good shot. It's nice to get a hole-in-one when you actually call the shot in advance and then pull the trigger.
"Today was a really tough day. The wind got stronger and stronger and it's definitely not easy out there. The wind and the conditions tests every aspect of the game.
"Standing over putts, you feel the wind on the body. It's a mental test out there but it's a fun challenge. I've been playing really solid golf and I'm excited to be where I'm at after two days."