The left side of the headache is not necessarily a brain tumor. It needs to be judged according to the patient’s age of onset, disease duration, characteristics of onset and examination, etc. It may also be caused by other diseases. Patients with brain tumor may have increased intracranial pressure due to intracranial tumor occupancy, edema of brain tissue around the tumor, tumor obstruction of cerebrospinal fluid circulation or bleeding inside the tumor, which may lead to headache, possibly accompanied by symptoms such as jet vomiting, vision loss and sensory impairment, mostly aggravated in the morning, when coughing or defecating, and the symptoms may be alleviated after vomiting, mostly manifested as pain in the whole head. In addition to brain tumors, migraine and hypertension can cause left-sided headache. Patients with migraine usually have recurrent attacks, while headaches caused by hypertension are usually accompanied by poor blood pressure control. If a patient has recurrent symptoms of left-sided headache or severe pain, it is recommended to consult the neurology department of the hospital as soon as possible to clarify the diagnosis by head MRI.