All students of fashion know how the 20th century transformed women’s clothing in the West. Corsets were loosened, hemlines rose, and designers like Coco Chanel and Yves Saint Laurent famously dressed ladies in trousers and tuxedo jackets.

Less documented was a similar fashion overhaul in China, which is now the subject of an exhibition at the Hong Kong Museum of History. “The Evergreen Classic: Transformation of the Qipao,” showing until Sept. 13, is a beautifully presented, and sometimes humorous, display of 280 Chinese gowns created over the last 130 years. The exhibition is augmented by photographs and commentary showing how the bulky Qing Dynasty robe — which covered everything but a woman’s face and hands — altered and shrank until it became the slinky “cheongsam” worn today, while retaining the gown’s distinctive diagonal lines. Unlike the Western dress, which has a vertical construction, the qipao follows the flow of wrapped fabric.

“We wanted to highlight the qipao’s role in history, and how it came to have greater meaning,” said Terence Cheung, assistant curator of the Museum of History. “The dress changed with the times.”...