Early symptoms of brain metastasis from lung cancer must be taken seriously. Early symptoms include: ①Headache: it is more intense in nature and often occurs in the early morning, sometimes waking up from sleep with pain, but the headache will gradually ease or disappear after getting up and doing light activities. ②Vomiting: due to the increase of intracranial pressure, the medulla oblongata respiratory center is stimulated, resulting in vomiting, which mostly occurs after the headache and is jet-like. ③Visual impairment: The increased intracranial pressure can cause poor venous blood return to the eye, causing bruising and edema, which can damage the visual cells on the retina in the fundus of the eye, resulting in vision loss. (iv) Mental abnormalities: Brain tumors located in the frontal lobe of the brain can destroy the neural activity of the frontal lobe, causing abnormal mental performance such as excitement, agitation, depression, repression, amnesia and fictitiousness.