Mirror tongue is a filiform papillitis, which mainly manifests as atrophy of the filiform papillae on the surface of the tongue and a smooth mirror-like back of the tongue, hence the name mirror tongue. Patients also experience burning and painful, numbing discomfort in the tongue. Mirror tongue is more common in middle-aged and elderly women as well as in frail and sickly patients. The systemic factors that cause mirror tongue include vitamin deficiency, anemia, fungal infection, etc. The local factors in the mouth are mainly the presence of residual roots and crowns in the mouth, excessive tartar and friction between the sharp tips of the back teeth on both sides. When the symptoms of inflammation are not obvious, it can be temporarily observed. The diet should be light, avoiding the stimulation of the tongue by overheated, spicy and hard foods, and the symptoms need to be supplemented with multivitamins if they are obvious. Candida infection should be removed from the cause, enhance the body resistance and antifungal treatment, and anemia should be consulted by an internal medicine doctor. In addition, it is necessary to remove intraoral lesions and treat dental and periodontal diseases.