Schwartzel, who won last week's Joburg Open, had nine birdies and a 17th-hole bogey at the Abu Dhabi Golf Club. He's one stroke up on Padraig Harrington, whose bogey-free round included a chip-in for an eagle at the 597-yard, par-5 eighth hole.
Niclas Fasth, Graeme McDowell and Alexander Noren are tied for third after shooting 66s Thursday.
Schwartzel birdied at the second hole Thursday and had three consecutive birdies from Nos. 4-6. After two pars he strung together four straight birdies to get to 8-under after 12 holes.
He finished with a birdie at 18 after the bogey at 17.
The Abu Dhabi field includes four of the top five ranked players in the world. No. 1-ranked Lee Westwood had a 3-under 68 and is tied for 15th. Martin Kaymer, third in the world and the Abu Dhabi defending champion, is in a tie for sixth at 5-under 67 and No. 4 Phil Mickelson is at 1-under 71. McDowell is the world's No. 5-ranked golfer.
No. 2-ranked Tiger Woods will open his 2011 season next week.