Multiple brain tumors are more likely to be malignant, but they must be judged according to the actual situation. The most accurate judgment is to rely on the pathological examination of the removed brain tumor cells and molecular judgment, while other tests such as CT, MRI and clinical symptoms are only approximate. In clinical experience, multiple brain tumors are mainly malignant, because only malignant ones may grow diffusely, especially in cranial metastases and gliomas, which may form intracranial spontaneous metastases, and the degree of malignancy is better.