Oral cancer is one of the most common head and neck tumors. Normally, the normal oral lining is pink or red soft mucous membrane. If a patient suffers from oral cancer, some precursors may appear, such as unexplained lumps without painful pressure in the mouth or neck, hard nodules in the oral mucosa, ulcers that have not healed for more than 4 weeks or incomplete opening of the mouth, numbness in the mouth, etc. Specific symptoms may be lumps, spots, ulcers, bleeding, pain, numbness, other symptoms, etc. Specific symptoms can be manifested as lumps, spots, ulcers, bleeding, pain, numbness, other symptoms, etc. 1, lumps: swelling, hard lumps, or long lumps are found inside or around the mouth. Lumps protrude from normal mucosa with different shapes. For example, the surface of lumps in squamous cell carcinoma is not flat and ulcers may occur. The lumps and ulcers caused by cancer are often hard and fixed at the bottom and cannot be moved easily; 2. Spots: white exfoliated patches or red spots caught in white spots can be found inside the mouth; 3. Ulcers: ulcers that cannot be cured for a long time; 4. Bleeding: repeated unexplained bleeding in the mouth; 5. Pain: numbness or pain in the parts near the mouth; 6. Numbness: due to tumor invasion, some patients will have lower lip Numbness: due to tumor invasion, some patients may experience numbness of the lower lip; 7. Other symptoms: patients may also have symptoms such as burning and dryness in the mouth, loose teeth, slurred speech and tongue movement disorder. In addition, if brown or black pigmentation suddenly appears in the patient’s oral cavity, and it shows sudden changes and rapid enlargement, the possibility of melanoma occurring in the oral cavity needs to be considered. If patients suspect that they are suffering from oral cancer, they can go to hospital for pathological section, ultrasound, magnetic resonance, PET-CT and other related examinations in order to get early diagnosis, so as to treat correctly and improve the chance of cure.