Derby-born Reid, 28, and 41-year-old Morgan, from Abergavenny, Wales, both hit four-under-par rounds of 68 in Shanghai, China.
Reid carded seven birdies and three bogeys, while Morgan holed five birdies in the back nine.
South Africa's Nicole Garcia also posted 68.
Britain's Melissa Reid and Becky Morgan are among three players who share the lead at the Buick Championship after the first round.