1. Oral mucosal cancer initially manifests as epithelial proliferative hard nodule, which is often not emphasized by doctors and patients. 2. Then the surface layer is eroded as ulcer, the surface is red with a few small white spots, shallow and without necrosis. Self-conscious symptoms of slight discomfort, occasionally irritating pain. This stage is also easy to be ignored and treated as a general mucosal ulcer. But careful palpation will feel the ulcer surface rough, edge slightly hard and tough with edge feeling. 3. Further development of the ulcer center necrosis, edge of the raised dike-like or petal-like outward, or necrosis phenomenon is not significant and nodular cauliflower-like proliferation. At this time, the patient’s self-conscious symptoms are obvious, often accompanied by dysfunction, but at this time, it is not the early stage of the tumor. 4. Therefore, the occurrence of progressive ulcers in the oral cavity, such as the lingual edge of the mandibular molars, the occlusal line of the buccal mucosa, the molar area of the upper and lower gums, etc., which have no tendency to heal after 2 weeks of general treatment, should be highly alerted to the occurrence of cancer. If the patients have the above symptoms, they should go to the hospital in time for clear diagnosis, early detection and early treatment so as to avoid delaying the condition.