Surgical resection is an important treatment for glioma, and the degree of surgical resection is closely related to the patient’s later treatment outcome. In other words, the more complete the tumor is removed during surgery, the better the patient’s treatment outcome and the longer the survival time. Therefore, the principle of glioma surgery is to remove as many tumors as possible under the condition of ensuring patient safety. However, a large part of glioma surgery is difficult to achieve complete removal, how is this? The difficulty in completely removing glioma during surgery is not due to the surgical technique, but mainly due to the characteristics of the tumor itself, in order to protect the patient’s safety. Specifically, the growth pattern of glioma makes it difficult to completely remove the tumor. Except for a few subtypes of glioma such as hairy cell astrocytoma and subventricular giant cell astrocytoma, which have relatively clear borders, most gliomas are diffusely infiltrating and have no obvious border with the surrounding brain tissue. Although the texture and color of gliomas are somewhat different from normal brain tissue, the border areas around gliomas are actually growing together with brain tissue, forming a situation where you have me and I have you. If we want to completely remove the glioma, we have to remove part of the brain tissue, which means we have to enlarge the resection area. In fact, there are areas of brain tissue that are functionally “dumb” that can be resected in this way to achieve a more complete extent. However, the distance and extent of glioma invasion to the surrounding area is very wide, and the “dumb zone” is limited, and most of the brain tissue cannot be damaged, so it is impossible to expand the resection area indefinitely, which makes it difficult to eradicate the few cells around the glioma that are mixed with normal brain tissue. The site of glioma growth is also an important factor affecting the complete removal of the tumor, but for most gliomas, the size is often so large by the time they are found that they have accumulated into the functional areas of the brain tissue. Sometimes, gliomas grow in important structures such as the brainstem, and in such cases, they cannot be enlarged or even removed to the border of relatively normal brain tissue in order to protect the important structures such as the brainstem. If the glioma is really removed to such an extent, the patient will have serious neurological impairment, and even serious disability and death, and the purpose of surgery to prolong the patient’s survival will not be achieved, so the glioma cannot be completely removed. Although many gliomas are difficult to be completely removed, subsequent radiotherapy, chemotherapy, electric field therapy and targeted and immunotherapy can be used to deal with the remaining tumor cells and prolong the patient’s survival time.