Starting the day one shot off the pace, McIlroy carded five birdies and three bogeys at Woo Jeong Hills Country Club to finish five under par alongside overnight leaders Rickie Fowler and YE Yang, with Moo Jung-kyung and Bronson La'Cassie completing the quintet.
"It was a good round. I felt it could have been lower but I played solid golf and holed some nice putts," the Northern Irishman told OneAsia's official website.
"It's a good start to the tournament and I have put myself in a good position going into the weekend."
Both Fowler and Yang signed for one-under 70s while Moo produced the best round of the day with a 66 that featured five birdies and an eagle two at the fourth. Australian La'Cassie, meanwhile, signed for a 67 with the leading group enjoying a three-shot advantage over Kim Meen-whee.
"I got it around and I am in a good position for the weekend, so that's a positive," said Fowler.
"I didn't hit it as well as the first round and I struggled with the speed of my putting over the last few holes, so I have some improving to do. But I am still in a good position for the weekend.
"It is a tough golf course and there are a lot of good players at the top of the leaderboard. I think the key for the weekend is driving the ball well and if I do that, I think everything else will fall into place."