BANGKOK, 12 Dec 2014 (AFP) - For the second day running, gusting winds and the thick rough troubled the entire field.
Fleetwood was on four-under for the tournament, with 2011 champion Lee Westwood and Australia's Marcus Fraser one shot behind.
A further stroke back were 24 year-old Thai national Tirawat Kaewsiribandit and Jonathan Moore of the US who shot 72 and 71 respectively.
Lurking in joint sixth place on one-under for the tournament were US Open champion Martin Kaymer, local star Thongchai Jaidee and Paul Peterson of the US.
Defending champion Sergio Garcia suffered a double-bogey at the 18th as he slipped back with a 75.
Joint overnight leader Thanyakon Khrongpha also had a bad day, struggling with a five-over 77.
"My game felt good," said Fleetwood who sunk four birdies and had just one bogey.
"I played really well and had only three or four bad shots, which is what you need in these windy conditions."
The 24 year-old Fleetwood, who won the Johnnie Walker Championship at Gleneagles last year, said keeping the ball out of the rough was the key on such a punishing course.
"Missing the fairways is like having a one-shot penalty," he said.
Westwood said he was very pleased with his 71, following his first round 70.
"I played very well again today. It's tricky out there and the wind was stronger than in the first round," he said, adding that "the rough is brutal" on the Amata course.
"All in all it was a good round and puts me in a good position for the weekend," the English star concluded.
Fraser said he was happy although did not play particularly well and needed some good putting to manage an even-par 72.
"I was pretty ordinary on the back nine, but managed to sink a few good putts to save par," he said.
The Australian, who suffered a long layoff this year due to a wrist injury, said he was especially sloppy at the third hole where he suffered a double bogey after struggling to get out of the rough.
"I was a bit amateurish and tried to get too greedy," he said.
Jaidee, who shot 71, also said he felt the day was demanding.
"The course was very difficult today," said the veteran Thai. "The rough is very thick and the greens are getting firmer. When the winds gets up it becomes a real challenge."
Bubba Watson, who fired a two-under 70 after a disappointing first round 76, said his putting was the key to his better score.
"I made a few puts early on and that gave me confidence," said the big-hitting left-hander. "I didn't hit any wayward shots and I got the momentum going."
But the American warned the course would remain tricky over the weekend if the wind keeps up.
The biggest casualty of the day, meanwhile, was French Ryder Cup star Victor Dubuisson who ballooned to 79 to miss the cut by some distance.
Leading scores after the second round of the $1 million Thailand Golf Championship at the Amata Spring course on Friday:
140 - Tommy Fleetwood (ENG) 71-69
141 - Marcus Fraser (AUS) 69-72, Lee Westwood (ENG) 70-71,
142 - Tirawat Kaewsiribandit (THA) 70-72, Jonathan Moore (USA) 71-71
143 - Thongchai Jaidee (THA) 72-71, Paul Peterson (USA) 71-72, Martin Kaymer (GER) 71- 72
144 – Koumei Oda (JPN) 74-70, Nathan Holman (AUS) 71-73, Anirban Lahiri (IND) 71-73, Scott Hend (AUS) 70-74, Lionel Weber (FRA) 75-69
145 - David Lipsky (USA) 71-74, Richard T. Lee (CAN) 69-76, Hung Chien-lao (TPE) 73-72, Anthony Kang (USA) 72-73, Berry Henson (USA) 73-72, Wang Jeung-hun (KOR) 73-72, Kang Sung-hoon (Kor) 75-70
Selected scores:
146 - Bubba Watson (USA) 76-70, Thaworn Wiratchant (THA) 72-74, Charlie Wi (KOR) 74-72, Thanyakon Khrongpha 69-77
148 - Kiradech Aphibarnrat (THA) 76-72
154 - Victor Dubuisson (FRA) 75-79, Jyoti Randhawa (IND) 75-79