Enlargement of submandibular lymph nodes is relatively common in clinic, of which the most common is bacterial lymphadenitis, and it may also be tuberculous lymphadenitis, malignant lymphoma, leukemia and lymph node metastasis of malignant tumors. 1. Bacterial lymphadenitis: it is mostly seen in bacterial infection in the oral cavity and pharynx near submandibular lymph nodes, which causes reactive enlargement of submandibular lymph nodes, mostly accompanied by pain. 2. Tuberculous lymphadenitis: Tuberculin test is mostly positive, and the patients may be accompanied by low-grade fever, night sweats (sweating abnormally after going to sleep, and sweating stops after waking up) and other typical manifestations, and the lymph nodes are mostly adherent with poor mobility. 3. Malignant lymphoma: submandibular lymph nodes can be enlarged and painless progressive enlargement, which can invade the surface skin, resulting in skin ulceration and not easy to heal. 4. Lymph node metastasis of malignant tumor: patients with malignant tumor foci can have enlarged submandibular lymph nodes when lymph node metastasis to submandibular lymph nodes occurs. It is recommended that the patient should consult the doctor in time and complete the auxiliary examinations in order to clarify the cause of the disease, and then the professional doctor should give the corresponding treatment to avoid delaying the condition.