Cancer brain metastasis may be asymptomatic in the early stages, and as the disease progresses, symptoms such as headache, brain dysfunction, and impaired consciousness due to brain herniation may occur. Cancer brain metastasis may cause headache, blurred vision and other nerve compression symptoms at the initial stage. As the tumor increases in size and compresses the brain functional area, symptoms such as blindness, hemiparesis and numbness of limbs may appear. If there is no timely treatment, the tumor will continue to grow and the intracranial pressure will be higher and higher, which may lead to brain hernia, drowsiness, coma, consciousness disorder, or even cardiac arrest and death. If the patient suspects that the tumor has brain metastasis, he should seek medical treatment as soon as possible to make a clear diagnosis and take targeted treatment as soon as possible to reduce intracranial pressure and prevent serious complications.