The survival time of patients with thymoma needs to be determined according to the size of the tumor and should be analyzed on a problem-specific basis. Thymoma is a tumor of the thymic area, usually located in the anterior superior mediastinum, and is overwhelmingly benign. The survival time of patients with this disease is related to the size of the tumor. If the tumor is found to be relatively small and has not yet compressed the surrounding lungs, heart or blood vessels, it can be cured by complete excision and does not affect the patient’s life expectancy. If the tumor is neglected at an early stage and continues to grow, it may compress the lungs, heart or blood vessels, and even after surgical treatment, the possibility of recurrence increases, which has an impact on the patient’s survival time. Thymoma has a certain possibility of malignant transformation and may recur or metastasize after surgical excision. If patients develop serious symptoms within a short period of time, it suggests the possibility of malignant transformation into malignant thymoma, which is more harmful to human body. Therefore, it is recommended that patients should be reviewed regularly to avoid delaying the disease.