Jose-Filipe Lima, who was one of six players tied for second after the opening round, remains in a share of second place at 8-under-par 136 after a 3-under 69 in round two. He stands alongside Prayad Marksaeng (67) and Marc Cayeux (65).
First-round leader Christian Cevaer struggled to an even-par 72 on Friday. He was joined in fifth place by Scott Drummond (67) and Rahil Gangjee (70) at minus-6.
Lynn played the back nine first on Friday and opened with birdies on 10 and 12 to move to minus-6. He birdied the 14th for the second straight round, but stumbled to a bogey on 15.
The 32-year-old bounced right back with consecutive birdies from the 16th to move to minus-8 at Honghua International Golf Club. However, Lynn faltered to a double-bogey 6 on the 18th to turn at 6 under.
Lynn caught fire on the front nine. He sank a birdie try on the second and came right back with a birdie on No. 3 to grab a share of the lead at 8 under.
The Englishman took the lead with a birdie at the fourth. Lynn then converted his fourth straight birdie at the par-5 fifth to get to 10 under. After parring his next three holes, Lynn tripped to a bogey at the ninth to close his round.
'Tee to green I won't say I'm at my best, but my putting has been nice,' said Lynn. 'If I can keep that going, then it will be good. You never know what is going to happen, but I'd rather be leading a tournament than chasing.'
As for that groin injury, Lynn was bitten by an insect prior to Thursday's round. The area became sore and inflamed so much so that he could not bend over to line up putts during the first round. Lynn, who was bitten by a scorpion in December at the dunhill championship, saw a doctor after his first round.
'After I played my first round, I went to see the doctor and he turned around and said that he needed to cut it out,' Lynn said. 'So he got his scalpel out and started to cut away. No anaesthetic or anything and I'm watching this whole thing take place. It was quite a big hole left, but he patched it up and did a great job.'
Cayeux birdied three of the first five holes to move to minus-4. He poured in three straight birdies from the eighth. The 28-year-old gave a stroke back to par with a bogey on the 11th. He atoned for that error with a birdie on 14 and moved into a tie for second as he birdied the 17th.
Marksaeng parred his first four holes as he started on the back nine in round two. He then dropped in back-to-back birdies from the 14th to get to 5 under.
The Thailand native parred four in a row around the turn, then birdied the second. Marksaeng birdied Nos. 5 and 7, each for the second day in a row, to end at minus-8 and close a bogey-free round.
Lima also started on the back nine. He birdied Nos. 11 and 14 for the second straight day to get to 7 under. Lima parred his next six holes before tripping to a bogey on the third. He sank consecutive birdies from the fifth to move into a tie for second then parred his final three holes.
Defending champion Paul Casey is tied for eighth at 5-under-par 139 after a 4-under 68. He was joined there by Jarrod Lyle, Terry Pilkadaris, Robert Coles, Simon Dyson, Peter Hanson, Nico Van Rensburg and Simon Yates.
The cut line fell at 1-over-par 145 with 69 advancing to the final two rounds.