Detective Chinatown 1900 (Chinese: 唐探1900) is a 2025 Chinese comedy mystery buddy film directed by Chen Sicheng and Dai Mo, starring Wang Baoqiang, Liu Haoran, with a special appearance by Chow Yun-fat. It is the fourth installment in the Detective Chinatown franchise. The film, which is set in San Francisco in 1900, follows the story of Qin Fu and Ah Gui's investigation into the murder of a white woman in Chinatown. The film premiered on 29 January 2025 during the Spring Festival.