The Swede closed with 2-under 70 to finish at 10-under 278 at the season-ending tournament of the Ladies European Tour.
'I am so happy to have finally won again,' Sorenstam said.
Overnight leader Iben Tinning of Denmark had a double bogey at the last hole and finished with a 73 to tie for second with England's Laura Davies, who shot a 72.
Six players, including halfway leader Lisa Hall, tied for fourth at 6-under 282.
Sophie Gustafson of Sweden won the Ladies European Tour Order of Merit after finishing 3-under and tied for 15th -- good enough to beat Bettina Hauert of Germany, who tied for 65th.
Gustafson earned $320,519 for the season compared to Hauert's $317,318.
For much of the last round at the Emirates Golf Club, it was a three-way battle for the title -- with Sorenstam, Tinning and Davies tied for the lead at 9-under after 10 holes.
Davies was the first out of contention with bogeys on the 12th and 15th holes, before finishing with a birdie on the 18th.
Tinning went to 10-under with a birdie on the 11th. She could have increased her lead on the 16th, but her birdie putt from 15 feet stopped just short of the hole.
Sorenstam joined Tinning at 10-under with a birdie on the 17th, where she made a 16-foot putt.
On the final hole, Tinning tried to make the par-5 green with her second shot, but the ball rolled back into the water guarding the front of the green. Sorenstam laid up and then made par for the win.
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