The 26-year-old Ochoa started with a birdie on the first hole and added six more on the back nine in a bogey-free round. Ahn Sun-ju, Candie Kung and Angela Park trail by one stroke.
Park, a 19-year-old Brazil-born South Korean who gained United States citizenship last month, began with eight pars before she birdied six of the final 10 holes. Annika Sorenstam had four bogeys in her round of 71, six shots off the lead.
Ochoa arrived at Europes richest womens tournament ' $487,500 goes to the winner ' after a three-week break since finishing 31st in the U.S. Womens Open. The Mexican star is a six-time winner on the LPGA this season.
I have my goal for the second part of the season, Ochoa said. Im very motivated to continue playing good and Im glad I got a good start.
Laura Diaz (67) shared third place, finishing with birdies on five of the last eight holes.
Like Ochoa, the 33-year-old American took a short break before Evian. She arrived in the French lakeside resort with a rib injury inflicted by her toddler son, Robert.
My son injured my right rib the Saturday before last and I was forced to withdraw from the Jamie Farr Classic, Diaz said. I took a whole week off and didnt hit a ball until I got here. I didnt even know if I was going to play.
Juli Inkster, Angela Stanford, Meena Lee and Suzann Pettersen also shot 67s.
In-kyung Kim, Young Kim and Amy Yang were another shot back, while defending champion Natalie Gulbis ' who played with Ochoa Thursday ' led a group at 69.
Sorenstam, the 2000 and 2002 Evian champion, played with Helen Alfredsson and Catrin Nilsmark in an all-Swedish trio of former winners.
Today I left a few shots out there, Sorenstam said. I felt good about everything, then I wasnt able to close.
We have a lot of holes to go. I have a good strategy. I know how to play this course.