The causes of submandibular lymph node enlargement are more numerous and complex, and the common clinical causes are mainly the following: First, submandibular lymphadenitis caused by bacterial infection, and severe stimulation will lead to reactive hyperplasia and enlargement of lymph nodes, and sometimes fever with local pain. Second, inflammatory stimulation of the tissues and organs surrounding the submandibular lymph nodes, such as oral infection, pharyngeal inflammation and abscesses in the apical root of the teeth, can cause swelling of the submandibular lymph nodes. Therefore, when submandibular lymph node enlargement occurs, it is important to find the specific cause and provide systematic treatment for the effective cause. In addition, some malignant tumors may also have distant metastasis, which is more serious. The best way is to find the primary focus, which can be found by simply doing pathological puncture biopsy of submandibular lymph nodes, which may not be able to find the primary focus completely, but can characterize the submandibular lymph nodes and find the primary focus as much as possible.