If he hangs on to win, Jaidee will become the first back-to-back winner of this event since Graham Marsh in 1974-75.
Jyoti Randhawa posted a 7-under 65 to move into second place at 13-under-par 203. Henrik Stenson (71), Padraig Harrington (67) and Prom Meesawat (71) are one stroke further back at minus-12.
Jaidee opened his round with a two-stroke lead and quickly stretched that with a birdie at the first. He moved to minus-16 when he drained a birdie at the third on the Palm Course at Saujana Golf & Country Club.
The 34-year-old stumbled to a bogey at the par-5 seventh. Jaidee erased that mistake with a birdie on the ninth.
Around the turn, Jaidee birdied the 11th and 13th, each for the third straight round, to jump to 18 under. The Thailand native was not done there.
Jaidee rolled in a birdie putt at the par-4 15th and moved to 20 under when his birdie try at No. 17 found the bottom of the cup. He faltered to a bogey at the last though.
'I had a good start on the front nine with birdies on the first and third holes which got me going,' Jaidee said. 'I hit my irons really well and putted nicely. Everything was perfect again today. It's nice to lead by six shots into the last round. My plan will be the same Sunday - fairways, greens and putts. I'm playing quite nicely and hopefully, I can go on and win this again. I'm feeling confident.'
Randhawa got his round going with a birdie on the par-5 third. At the next par-5, No. 7, the India native converted an eagle to jump to 9 under. He came right back with a birdie on the eighth to keep rolling.
The 32-year-old got to 11 under when his birdie try at 11 fell into the cup. Randhawa picked up the second eagle of his round at the par-5 13th from 20 feet out. He stumbled to a bogey on 16, but came back to birdie 17 to get back to 13 under.
'It seems tough and Thongchai looks to be playing well and he's a good player. But what can you say in golf,' said Randhawa on his thoughts of chasing down Jaidee. 'A guy on 11 under can come from behind and win. One more day to go and I'll take my chances tomorrow.'
Harrington, the top-ranked player in the field, birdied three of his first five holes to climb the leaderboard. He traded two birdies for two bogeys over a six-hole stretch from the ninth before closing his round out with birdies on each of the last two holes.
'Two birdies to finish, I'm happy with that,' said Harrington, the eighth ranked player in the world. 'Thongchai obviously likes it here. It is within his hands and he is totally in control. Even if I shoot a low one, I have to depend on him.'
Thomas Bjorn played in the final group with Jaidee, but went the wrong way Saturday. He tripped to a 1-over 73 to slide back to 11-under-par 205.
Stuart Manley used a 6-under 66 to climb into a tie for seventh place. He was joined at minus-9 by Robert-Jan Derksen, Pelle Edberg, Simon Yates, David Bransdon and Peter Gustafsson.