Tseng began the final round on stroke behind Al Miyazato but matched the day's best round for a 6-under-par 66 and a 72-hole total of 19-under 269 in winning her 13th LPGA championship and 21st overall title.
Tseng fought back from an opening round of 1-over 73 with back-to-back 65s in the second and third rounds before closing with a eagle, six birdies and a pair of bogeys in Sunday's round of 66.
She pulled into a tie for first with an eagle at the par-5 first hole Sunday, where Miyazato had a birdie. Tseng was ahead by four strokes at the turn after she had three birdies on the front side while Miyazato had three bogeys and two birdies after the opening birdie.
Miyazato pulled close, however, with a pair of birdies through 15 against two bogeys and a birdie from Tseng. But, even through Miyazato had birdies at 17 and 18, Tseng matched that to secure the win.
Her approach at the 18th nearly went in for eagle, leaving her a tap-in for the title.