Multiple lymph node enlargement in the mediastinum means that on CT, the lymph nodes in the mediastinum of the chest cavity are seen to be much larger than the normal diameter and show multiple changes. This condition is considered in the clinic including benign lesions, tumor factors, etc., as follows: First, benign lesions: benign lesions such as lymphadenitis in the mediastinum, or reactive hyperplasia of lymph nodes in the mediastinum induced by infectious lesions in the chest, and some atopic infections, including lymphatic tuberculosis in the mediastinum, as well as silicosis, allergic reactions and allergic diseases, can lead to enlarged lymph nodes. Second, tumor factors: more serious diseases include thymoma, lymphoma, as well as lung cancer in the mediastinum, and other malignant tumor metastasis resulting in enlarged lymph nodes in the mediastinum. In short, when multiple lymph nodes in the mediastinum are enlarged, we must pay great attention to it, find the specific cause, and then carry out systematic and standardized treatment according to the cause.