Brain tumors may present with a variety of different symptoms, but epilepsy is one of its common symptoms. Some patients with brain tumors present with epilepsy at the very beginning, while others have epilepsy as their only symptom, and these are called brain tumor-associated epilepsy. Various types of gliomas, meningiomas, and brain metastases that are common in brain tumors are prone to epilepsy at different stages of the disease. Brain tumor-associated epilepsy may take various forms, ranging from partial seizures, such as convulsions of the limbs, to generalized seizures with transient loss of consciousness. Mr. Kang is such a patient with brain tumor-associated epilepsy. He started to have mild headache half a year ago but did not pay attention to it, and then half a month ago he suddenly fainted on the ground, foamed at the mouth, rolled up his eyes, and had convulsions in his limbs. This is a typical manifestation of a grand mal seizure, commonly known as “crohns”. The MRI soon revealed a tumor with a maximum diameter of 7 cm in the left frontal lobe, and the pathological diagnosis after surgery confirmed that it was a WHO grade III mesenchymal astrocytoma, IDH mutation type, which belongs to a type of glioma. Epilepsy can be caused by a variety of reasons during the course of a brain tumor, but can be broadly divided into factors of the brain tumor itself and treatment-related factors. In terms of the brain tumor itself, during the growth process, the tumor itself or secondary hemorrhage, edema and other stimulation, compression and destruction of the surrounding brain tissue, or the brain tumor itself has neurons or glial cell components, which causes abnormal discharges of neurons in the cerebral cortex around the brain tumor triggering epilepsy. Therefore, brain tumors located in the supratentorial region close to the cerebral cortex are prone to cause epilepsy, while tumors located in the infratentorial region of the cerebellar tissue are rarely epileptic. From a therapeutic point of view, various treatments during brain tumor treatment may cause epilepsy. In some brain tumors, epilepsy can be better controlled after surgical resection of the tumor, but it may be further aggravated, and even patients with brain tumors that were previously free of epilepsy may develop epilepsy after surgery, as scars from tumor resection, for example, may also cause epilepsy. Radiotherapy of the tumor after surgery may lead to secondary changes such as edema causing epilepsy, and all kinds of drugs during tumor treatment, including chemotherapeutic drugs, have the potential to cause epilepsy. Epilepsy is a common symptom of brain tumors. Throughout the treatment of brain tumors, in addition to controlling the growth of the tumor, attention needs to be paid to controlling seizures in order to improve the quality of life.