"I think today is pretty good round for me," Lin said.
"Actually when I played in the practice round, I thought, this place is pretty tough, and also I'm pretty surprised what I'm doing today. So I'm really satisfied with my game today."
The $2 million event is the penultimate leg of the LPGA Tour's five tournament Asian swing which has seen Ko retake the top spot in the world rankings from South Korea's Park In-bee after two top five finishes and a win in Taiwan last week.
Following her nine-shot win in Taiwan, Ko did not arrive in China until Wednesday which could have been a factor in her sluggish start following an opening par.
Ko went double bogey, bogey, bogey, bogey from the second with another two dropped shots on the 11th and 12th leaving her at seven-over.
She recovered with two late birdies to sign for a 77, one less than a six-over 78 she carded at the LPGA Tour's Kia Classic in California last year.
Lin has also enjoyed a solid Asian swing with top seven finishes in Taiwan and Malaysia to rise up to 72nd in the world rankings.
She began her round with a birdie three and another gain at the par-three 17th allowed her to move one clear of American Austin Ernst (68).
Blustering winds made scoring tougher as the day went on with the lead duo among a group of only 10 players under par, including American world number three Stacy Lewis (71).
(Writing by Patrick Johnston in Singapore; editing by Sudipto Ganguly)