The fire broke out in a narrow alley packed with wooden houses on Yaowarat Road at nearly 9 p.m. and more than 30 firefighters were dispatched to the scene, Bangkok Post reported.
It took three hours to bring the fire under control.
No fatalities were reported but 30 people required medical treatment after suffering from smoke inhalation.
The fire damaged part of the three-star New Empire Hotel, The Nation Thailand reported.
A witness said he heard several loud explosions, apparently from a transformer before the fire broke out.
Police are investigating.
Chinatown in Bangkok, famous for its vibrant street markets, authentic cuisine, and rich cultural heritage, has recently garnered interest from tourists after it appeared in the music video ‘Rockstar’ by Blackpink's Lisa.