Compared with conventional radiation therapy, heavy ions have significant advantages when used in cancer treatment due to their physical and physical properties of concentrated dose loss at the end of the range and high relative biological effects. They have the least damage to healthy tissues around the lesion, the best killing effect on cancer cells, precise online monitoring of irradiation location and dose, short treatment course, no pain, and almost no side effects. Therefore, heavy ions are internationally recognized as the most ideal radiation therapy for the 21st century, and are particularly suitable for difficult to treat cases that are ineffective or prone to recurrence in surgery, chemotherapy, and conventional radiotherapy. At present, developed countries such as the United States, Japan, and Germany have treated over 6000 cases of various cancers with this method.