Brain-computer interface （BCI） is a new human-computer interaction method or technology that breaks through the conventional limitation of peripheral neuromuscular efferent pathway and enables people to directly control external devices through brain signals. BCI usually uses surface electroencephalogram to obtain characteristic EEG. The basic process includes signal collection， pre-processing， feature extraction， classification and equipment control. BCI usually uses surface electroencephalogram to obtain characteristic EEG signals. BCI can assist patients to communicate with the outside world and move， real-time control of prosthetic limbs， orthosis， nursing robots and other rehabilitation aids， help them rebuild motor function and reduce life dependence， or carry out feedback training， activate or improve nerve plasticity， and rebuild nerve function.