O'Malley three times had back-to-back birdies to make the top of the tight leader board that shows 50 players within five shots of the lead. Mikko Ilonen, Jeev Milkha Singh, Henrik Stenson and Oliver Wilson, all at 4-under 68, were closest to O'Malley.
O'Malley, starting at No. 10, opened his round with consecutive birdies and moved to 4-under with birdies at Nos. 15 and 16. He had a bogey at 18 but grabbed the outright lead with birdies at Nos. 5 and 6.
"I drove the ball beautifully," O'Malley said. "I had one green where I had to chip to and missed two more by a foot on the fringe, so my iron play was great as well and I couldn't find any fault with that."
The tournament is the second in China in two weeks for the European PGA Tour, which returns to Spain next week. Damien McGrane won last week's Volvo China Open in Beijing.