Stanford followed her course record and career-best 10-under 62 on Thursday with a scrambling 3-under 69 on Friday for a 13-under 131 total.
Ochoa, the event's defending champion and world's top-ranked female golfer, was one back at 12 under. She began the day three strokes back and shot a steady 67.
Jee Young Lee was three back at 10 under, while Annika Sorenstam shot a 67 to join Michele Redman (68) at 8 under, five off the lead on the 6,662-yard course at the Superstition Mountain Golf and Country Club.
With the crowd behind her and the surroundings familiar, Mexico's Ochoa felt at home on this desert course.
"I just love being here," she said. "For sure we only play once a year in a desert golf course. And I just feel comfortable. It feels good, and it brings me good memories. I love Arizona, and I want to take advantage of that only one opportunity."
Ochoa attended the University of Arizona, and she is concerned that Safeway is ending its sponsorship of the LPGA Tour's lone Arizona event after this year to concentrate its efforts on the tournament it holds in Portland, Ore. The LPGA Tour left Tucson in 2004.
"If there is anything I can do to help have a sponsor next year, let me know," Ochoa said. "And not only me, but all of the players as a group. I think we would all love to be back."
Stanford was pleased that she didn't falter too much after her big first round.
"After shooting, well, a career round for me, you really don't know what to expect the next day," she said. "So I really tried to keep the same mind-set and give myself chances and just roll my putts."
A winner once in seven years on the tour, Stanford took up where she left off with birdies on her first three holes Friday to go to 13 under. But, playing the back nine first, she had bogeys on a three par-5s
- the 16th, 18th and second - to fall to 10 under.