Mediastinal tumor is a relatively complex type of tumor, which mainly grows inside the mediastinum. The anatomical position of mediastinum is between two sides of the chest cavity, in front of which is the sternum, behind which is the spine and both sides of the spine, the upper part is connected with the neck, and the lower part is connected with the abdomen, which is a narrow and long lot and very crowded. Mediastinal tumors are generally a kind of complex tumors with the following three main features: 1) they grow in the long and narrow part of the mediastinum and may cause some compression symptoms, such as compression of heart vessels, lungs, trachea and esophagus; 2) there are benign and malignant mediastinal tumors, and if they are malignant, they may involve important organs of the mediastinum, such as heart, blood vessels, trachea and esophagus, which may endanger the life of the patient in severe cases; 3) mediastinal tumors are life-threatening; and 4) they are very dangerous. Mediastinal tumors are very complicated, divided into anterior mediastinum, middle mediastinum and posterior mediastinum tumors, and the complexity of tumors in different places is different, such as thymoma and lymphoma, which sometimes have great difficulties in diagnosis.