The possible causes of submandibular lymph node enlargement are: lymph node inflammation, cervical lymph node tuberculosis, nodal disease, lymphoma, metastasis of malignant tumors and so on. 1. Inflammation of lymph nodes: submandibular lymphadenitis is mostly caused by the spread of infections in neighboring areas, such as gingivitis, oral mucositis, tonsillitis, etc. Most of them can subside by themselves after the primary infection is controlled. 2. Cervical lymph node tuberculosis: cervical lymph node tuberculosis is mostly secondary to oropharyngeal tuberculosis infection, tuberculosis mycobacteria invasion can stimulate the lymph nodes to appear painless enlargement, and when the lymph nodes are fused with each other, they can form a soft tissue mass. 3. Nodular disease: Nodular disease is a kind of multi-system inflammatory granulomatous disease that involves the whole body, and it occurs in the lungs and lymph nodes, mostly in the lymph nodes of the neck, groin and other parts of the body, which manifests as painless enlargement of lymph nodes, which can be pushed and do not merge with each other. 4. Lymphoma: Lymphoma is a malignant tumor of lymphatic tissue origin, which can occur in lymph nodes all over the body. Patients manifested as painless progressive enlargement of lymph nodes, which may be accompanied by low-grade fever, night sweats, itchy skin and other systemic manifestations. 5. Lymph node metastasis of malignant tumors: thyroid cancer, nasopharyngeal carcinoma, head and neck malignant tumors are prone to metastasis of adjacent lymph nodes and cause submandibular lymph node enlargement. It is recommended that patients with enlarged submandibular lymph nodes should go to the hospital as soon as possible to get a clear cause of the disease and be treated accordingly.