Brain-Computer Interface usually refers to a new type of information exchange and control channel established between the brain and the external environment, independent of the conventional spinal cord and peripheral nerve muscle tissue, which can realize direct interaction between the brain and external devices. Brain-computer fusion is to use Brain-computer Interface technology, drawing on the information processing methods of the brain, to achieve a deep fusion of biological brain intelligence and computer brain intelligence. This chapter discusses Brain-computer Interface and Brain-computer fusion, detailing the technical framework of Brain-computer Interface, representative Brain-computer fusion models, and several examples of Brain-computer fusion applications. Finally, it discusses the problems and adjustment strategies of Brain-computer Interface and Brain-computer fusion technology in the development of human-computer interaction, and looks forward to the future development direction. From a human-centered AI (HCAI) perspective, the purpose of brain-computer interface and brain-computer fusion research is to ensure that such technologies are designed, developed, and implemented in ways that empower humans, enhance their capabilities, and respect their values, needs, and ethical considerations.