According to the guidelines for surgical resection of gliomas, it is recommended that gliomas be resected to maximize safety, that is, to remove the maximum amount of tumor as safely as possible. How should this be understood? We need to understand the following questions: 1. Where exactly is the boundary of glioma? Wouldn’t total resection be better? Why is total resection not even recommended but maximum resection? 2. What is the maximum size? What are the criteria for maximum? 3.What is the meaning of safety? No postoperative bleeding, infection, etc.? Or no damage to nerve function? At present, there are at least two descriptions for the boundary of glioma: imaging boundary (the boundary shown by MRI) and cytological boundary (the boundary of tumor cells), most of the imaging boundary can be determined by MRI, while the cytoma boundary is much larger than the imaging boundary, and there is no good method to determine where it is. Therefore, resection of the tumor according to the imaging boundary is not a total resection of the tumor. In clinical practice, the general resection range is often larger than the imaging boundary, so we can only say maximum resection, but not total resection. 2. Maximum resection and safety are not contradictory, but on the contrary, they are the best fit. In clinical practice, after resecting the imaging boundary of the tumor, we continue to expand the resection to the functional brain boundary (maximum) in order to maximize the resection of the tumor without causing neurological dysfunction. 3. So where exactly is the functional brain boundary? The surgery that does not affect the brain function is safe. Brain tissue is the most mysterious organ in the human body. Theoretically, every part of brain tissue is involved in certain functions and there is no absolute functional dumb zone. Brain function is understood on many levels and can be basic speech, motor, and visual functions. It can also be higher brain functions, such as executive, decision making, judgment, etc. Different social attributes have different requirements and implications for functional preservation. Therefore safety excision is a big proposition, there is no absolute safety, only relative safety.