Last season's Order of Merit winner recorded a five-under-par 67 for a two-day total of eight-under-par 136 to move a stroke ahead of local player Hsu Mong-nan (68) and India's Chiragh Kumar (69).
Thaworn, who won the tournament in 2010, struggled with his iron play but dazzled in and around the greens, which also impressed playing partner Jonathan Moore of the United States, who carded a disappointing 75.
"I hit about four greens but I was saved by my chipping and putting. Jonathan said he was watching a $100,000 short game golf clinic," the 46-year-old Thaworn, who holed a 19-yard chip-in birdie on the 11th, told reporters.
"There hasn't been any rain lately so the greens are hard. Some players find it hard to play here but I like playing on this course.
"I won't say that I have a good chance to win yet because my irons are not where I want them to be."
The experienced Thai, who has 15 Asian Tour titles, had a lone bogey on the 16th after picking up four more shots following his 10-foot eagle putt on the opening hole.
Overnight leader and fellow Thai Thitiphun Chuayprakong dropped down into a tie for ninth after firing a four-over-par 76 to leave him on two-under for the tournament, alongside defending champion Gaganjeet Bhullar of India, who carded a 69.
The halfway cut was set at four-over-par 148 with a total of 77 players qualifying for the weekend at the Linkou International Golf and Country Club near Taipei
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