Ochoa shot a 71 in the final round for a 12-under 204 at Columbia Edgewater Country Club for her sixth victory of the season.
In-Bee Park (64), Christina Kim (69), Sophie Gustafson (75) and Mhairi McKay (72) all finished at 7-under 209.
The top-ranked Ochoa, from Mexico, won the Canadian Women's Open in Edmonton, Alberta, the previous week. Before that, she won the Women's British Open for her first major title.
'It's hard to describe how I'm feeling today,' she said. 'It was a great week and a great day.'
Ochoa, playing with Gustafson and McKay, was followed by a sizable gallery, including a sponsor's group of some 150 fans from Guadalajara. Many waved the Mexican flag.
The large crowd following Ochoa and her sizable lead prompted tournament officials to let fans watch from the fairway when Ochoa was on the 18th green.
The last player to win three straight tournaments was Annika Sorenstam in 2005. Sorenstam won four straight in 2001, matching the LPGA record.
Ochoa dedicated the title to her mother, whose birthday was Sunday. Ochoa planned to take a month off to spend time with her family.
'This tournament is for her. I can't wait to see her,' she said.
Ochoa's day didn't start well, with a pair of bogeys on the first three holes. But then she settled.
She played mostly at par on the back nine, missing a couple of opportunities to widen the margin. After a 7-foot birdie putt lipped out on the par-5 12th hole, Ochoa flipped her putter in disappointment.
But Gustafson, who started the day a shot back of Ochoa and stayed close through the front nine, had trouble on the back and double bogeyed the par-4 17th hole. McKay, from Scotland, also double-bogeyed the 17th. Ochoa bogeyed it.
Gustafson, from Sweden, has not won on the LPGA Tour since 2003. Her best finish this season was a tie for fifth at the Safeway International. McKay has not won on the tour.
The best round of the final day was 64, shot by rookie In-Bee Park of South Korea. She started the day at 1-over.
Park made five straight birdies during one stretch, playing behind Ochoa's group after starting from the back nine.
'I really didn't feel like I was making five in a row, because we had to wait for every shot,' she said, adding: 'I think it helped me because I definitely played well today.'