Ochoa, who started on the 10th hole, and Sorenstam were 9-under 137 overall. Ochoa, ranked second in the world behind Sorenstam, had eight birdies, one eagle and two bogeys. Sorenstam shot a course-record 66 on Thursday.
Ochoa's eagle came on the par-5 17th, one of the longest on the Bro-Balsta course, where she hit a 6-iron within 9 feet of the pin.
'I played really well and it felt much easier than the first round,' Ochoa said. 'I made some putts. I needed to play aggressive. Now I'm in a good position for the weekend.'
Sorenstam shot a 2-under 71, picking up her first bogey in the tournament on the 11th hole. She had three birdies.
'It's always tough to follow up a round of 7 under, but I think I played well today -- better than my score suggests,' Sorenstam said. 'But I didn't get any breaks with my bounces and putts.'
Gwladys Nocera, the Ladies European Tour money leader from France, shot a 69 and was one stroke behind the leaders. Helen Alfredsson, the Solheim Cup captain from Sweden, was another stroke behind after a 70.
Suzann Pettersen shared fifth with Karen Stupples at 140.
Sherri Steinhauer, who won last week's Women's British Open, slipped to a 76 and was tied for 16th at 144. She started with three straight bogeys and had no birdies.
Sorenstam, who started playing golf at 12 on the Bro-Balsta course, is the tournament host. She won the inaugural event last year at Barseback.
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