Oral cancer is a general term for malignant tumors occurring in the oral cavity, most of which belong to squamous epithelial cell carcinoma. Early detection of oral cancer tumors is of great significance for treatment and prevention, and should be given sufficient attention. The main manifestation of oral cancer is a lump. The lump on the surface can be observed, while the lump in the deep part or in the jaw bone can be touched because of bulging, or detected because of asymmetry between left and right, and it usually grows fast and can grow to a large size in a short time. There are also many oral cancers that present as ulcers with infiltrative growth. Hard lumps can be palpated at the base and around the ulcers, with elevated and untidy edges and depressions in the middle, with granular bumps on the depressed surface covered by necrotic tissue, which are usually painless or painful after irritation, and can have spontaneous pain when invading nerves. Therefore, ulcers that are more than 2 weeks long need to be closely observed, and if they do not heal, medical consultation is required to confirm the diagnosis. Oral cancer occurring in the jawbone, due to the destruction of alveolar bone, may show symptoms such as loosening and displacement of teeth and bleeding of gums; due to the growth of cancer, compression and invasion of nerves, corresponding neurological symptoms will appear. For cancer in the mandible, the early symptoms may be severe and continuous pain, numbness of lower lip, etc.; for cancer in the maxilla or maxillary sinus, the early symptoms may be numbness sensation of face or upper teeth. Due to the rapidly developing oral cancer, it invades the masticatory muscle group and temporomandibular joint, which can cause the limitation and difficulty in opening and closing mouth movement. The above are the common early symptoms of oral cancer, but it does not necessarily mean that the above symptoms are oral cancer. We must be vigilant, and once found, we should immediately consult for examination, so as to achieve the purpose of early detection, early diagnosis and early treatment.