An oral optical diagnosing apparatus and operating method are disclosed. The oral optical diagnosing apparatus includes a positioning module, an optical sensing module, a processing module, and a display module. After the positioning module selects a region to be diagnosed in a mouth, the optical sensing module will perform optical sensing on the region to be diagnosed to obtain optical information related to the region to be diagnosed. The processing module is used to analyze the optical information to generate an optical diagnosed result. The display module is used to display the optical diagnosed result.
