Abstract: A 3.5-year-old domestic shorthair cat presented to the doctor due to recurrence of oral inflammation, which suffered from depression, anorexia, ptyalism, halitosis and dysphagia. Physical examination revealed severe ulcers and hyperplasia in the gums, buccal mucosa, upper jaw, tongue, and pharynx; a mass was found under the tongue of the cat with residual tooth roots. In order to diagnose and treat the cat’s disease, X-rays were used to check the residual tooth roots. At the same time, surgery was performed to remove the cat’s sublingual mass, and histopathological analysis was performed on the removed mass. Meanwhile, the basic body condition of the cat was evaluated through blood routine and blood biochemical indexes examination, and the common pathogens related to cat stomatitis were screened by RT-PCR/PCR method. The results showed that after the X-ray examination confirmed the condition of the residual tooth root, the cat was surgically removed the sublingual mass and the residual tooth root was removed; according to the oral symptoms and the histopathological test results of the mass confirmed that the cat had chronic gingivostomatitis. Routine blood results suggest that the cat had inflammation and mild anemia. Pathogen screening detected Feline immunodeficiency virus and Feline calicivirus associated with chronic gingivostomatitis. With the use of antibiotics and interferon after the operation, the clinical symptoms of the cat were significantly alleviated. However, the gingivostomatitis recurred in the cat 18 months after the operation. At this time, the pathogen screening only found that the Feline immunodeficiency virus was positive. It was speculated that immunosuppression caused by Feline immunodeficiency virus was the main cause of chronic gingivostomatitis in this case. The results suggested that for recurrent cat chronic gingivostomatitis, attention should be paid to screening for related infectious pathogens in order to give the cats appropriate daily care.