Biomedical engineering is a discipline that integrates biology and medical engineering to solve problems in the medical field through the application of engineering techniques and principles. Brain-computer interfaces are an important research area in biomedical engineering, which involves connecting the human brain to a computer or other external device for monitoring, controlling and intervening in brain activity. In the treatment of depression, brain-computer interfaces can be used to improve a patient's emotional and psychological state by stimulating specific brain regions or modulating electrical brain activity. This treatment has the potential to become a novel treatment for depression.