South Korean Yang birdied her last two holes for a six-under 66 to win the season-ending CME Group Tour Championship by three shots at 27-under 261 and claim the $US2 million ($A3.07m) prize, matching the largest in women's golf.
Sunday's victory at Tiburon GC in Naples, Florida, was her fifth on the LPGA Tour, the previous four coming in Asia.
The 34-year-old Yang holed out for eagle on the 13th fairway to overcome an early three-shot deficit, and then she let Japan's Nasa Hataoka make the mistakes in crucial moments down the stretch. All 60 players who qualified for the season finale only had to win to become the Race to CME Globe champion.
Hasaoka shot a 69 and American Alison Lee had a 66 as they tied for second.
American Lilia Vu, a two-time major champion this year and No.1 in the women's world ranking, closed with a 65 to finish alone in fourth, three shots further back and picked up a valuable prize of her own. She won the points-based LPGA player of the year for the first time
Leading Australian Minjee Lee could make no inroads on the final day, shooting a 70 to tie for eighth, nine shots behind Yang, while Hannah Green (70) was a further six shots back in a tie for 23rd with Grace Kim tied 47th after a 76, Sarah Kemp (72, T50th) and Steph Kyriacou (76, T57th).
Yang trailed by thee shots through six holes of the final round when she charged back into the mix with three birdies over a four-hole stretch.
The pivotal shot was holing out her approach on the par-4 13th, the ball landing near the pin and then spinning back about 6 feet into the cup.
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