The 32 year old, who secured a top-ten finish at the US PGA Championship two weeks ago, shot a five under par 67 at Burapha Golf Club to join Thailand's Pariya Junhasavasdikul and Andre Stolz from Australia at the top of the leaderboard.
Liang, whose only European Tour win was in 2007, already has a OneAsia tour title to his name this season after claiming the Luxehills Chengdu Open in April and made a solid start in his bid for a second win of the year with three successive birdies from the second.
"It was an okay day," he said. "On my front nine I had a lot of birdie chances but missed many putts. I was a bit tired and needed to wake up and do something, which is what I did. The back nine was far better.
"I like the course. Today was fine but it depends what I can do on the next three days."