Ochoa, who leads the LPGA Tour money list, was joined atop the leaderboard by Shani Waugh and Mi Hyun Kim, who has already won twice this year.
Women's world No. 1 Annika Sorenstam, the 2000 and 2002 champion, posted a 3-under-par 69. She stands alongside Michelle Wie, Suzann Pettersen, Michele Redman, Wendy Ward and Heather Young in a tie for eighth.
Sorenstam was plus-1 through seven holes, but birdied eight and eagled nine to make the turn at minus-2. She dropped another stroke at the 14th, but birdies on 16 and 17 got her to 3 under.
'I think I played a little better than the score,' Sorenstam said. 'It was tough to make putts today and I felt like I left a few out there, but you know it's the first day, it's not too bad.'
The 77-player event is co-sponsored by the LPGA and the Ladies European Tour. Jennifer Rosales was in the field, but did not start and was not replaced. There is no cut for this event so all players will compete for 72 holes.
Ochoa, who has also won twice this year, converted back-to-back birdies from the second and again from the sixth to move to 4 under. Around the turn, she birdied the 10th at Evian Masters Golf Club.
The Mexican moved into a share of the lead at minus-6 with a birdie on the par-4 12th. Ochoa came right back with a birdie on 13 to move to the top of the leaderboard.
However, a bogey on the par-5 15th dropped her back to minus-6. Ochoa parred the last three holes to remain tied for the lead.
'I did play very good today. I hit the ball very solid,' admitted Ochoa. 'I think I only missed one driver and that was the bogey I made, but besides that I feel very comfortable with the way I am hitting the ball. I hit it close today and did not have that many long putts. It worked so hopefully I can do the same thing the next three days.'
Kim came flying out of the gates with five birdies over the first seven holes. She stumbled to a double-bogey on the par-3 eighth, but bounced right back with a birdie on No. 9.
The 29-year-old Korean birdied the 12th and 13th to get to 6 under. Kim faltered to a bogey at the par-3 14th. She atoned for that mistake and gained a share of the lead with a birdie on the par-5 18th.
'Last week was an off week and I had a four-day lesson with my coach,' Kim stated. 'We made my swing a little more compact and it is working. I had some great shots today and every shot felt comfortable. My putting was good and I feel more comfortable with my short game too, so I think that is why I played well today.'
Waugh birdied the first three holes at the start of her round. She came back with birdies at five and seven as she made the turn at 5 under.
The 36-year-old dropped a stroke with a bogey at the 12th. Waugh closed with birdies on 16 and 18 to end at 6 under.
Defending champion Paula Creamer leads a group of six players tied for 14th at 2-under-par 70.