Cranial gamma knife also has contraindications. There are mainly the following aspects: (1) intracranial aneurysm: Gamma knife early on the aneurysm of the attempted treatment, in general, not many cases of treatment worldwide, and then excluded from the indications for gamma knife. The main reason is that the arterial blood flow is too fast to be easily occluded, and the risk of rupture and bleeding of the aneurysm at any time does not allow the gamma knife to do long-term follow-up observation of the efficacy. Only those who are difficult to embolize and cannot be craniotomized and located in the distal end of the internal cerebral artery microaneurysm and AVM malformation in the nest combined with microaneurysm and can not be embolized can consider gamma knife treatment. I think it is better to classify simple cerebral aneurysm as a contraindication, so as not to cause clinical confusion. (2) Huge brain tumor: the intracranial tumor is huge, the intracranial pressure is increased significantly, and the midline brain structure is obviously shifted to the opposite side. At this time, patients show severe headache, malignancy, vomiting, etc. (3) Intracranial cystic lesions: brain cysts and cholesteatoma are contraindications to gamma knife. Cystic craniopharyngioma is not suitable for treatment by gamma knife first, and its cystic wall can be considered for treatment by gamma knife only after craniotomy or stereotactic surgery to release the cystic fluid to prevent recurrence. (4) Brain tumor combined with obstructive hydrocephalus: It is mostly seen in patients with tumors in the three ventricles, four ventricles and pineal region. If germ cell tumor causes mild obstructive hydrocephalus, it can be treated with gamma knife under close observation. If the hydrocephalus is more serious, regardless of the lesion, ventriculo-abdominal shunt or craniotomy should be performed first to relieve the hydrocephalus before considering gamma knife treatment. (5) Giant tumor in the saddle area: If the tumor has significantly compressed the visual pathway, the patient’s vision and visual field are severely impaired, and he/she is facing blindness in the near future. Such patients should first consider craniotomy, and then consider gamma knife treatment if there is a residual tumor after surgery. (6) Tumor in the medulla oblongata: the medulla oblongata is the most important part of the brain. This part of the tumor gamma knife treatment can also occur similar to the risk of craniotomy. The author treated a case of medullary metastases many years ago, despite the marginal dose of only 9Gy, but the patient died of respiratory and circulatory failure a week later. The author is cautious about gamma knife treatment of tumors in the medulla oblongata and should be treated as a contraindication. If the medulla oblongata peripheral lesions involving the medulla oblongata and compression is not serious before gamma knife treatment can be considered, but the dose must be controlled. (7) intracranial lipoma. (8) Brain parasites: such as brain cysts, brain worms, etc. (9) Intracranial inflammatory lesions: such as brain abscess. (10) The patient’s general condition is very poor, severe cachexia can not tolerate gamma knife treatment.