The cochlear implant, also known as the electronic cochlear implant, is in fact a special kind of acoustic-electrical conversion electronic equipment, belonging to the high-tech electronic medical products. It is generally divided into two parts: in vivo and out-of-vivo, and is mainly used to help profoundly deaf and totally deaf patients to gain hearing, especially those who have been ineffective in wearing conventional hearing aids. The inner machine is surgically placed in the cochlea of the inner ear and the outer machine is fixed to the skull. The external machine converts mechanical sound energy from the surrounding environment into electrical signals, which in turn stimulate the cochlea and auditory nerve to produce hearing. After cochlear implantation, the key is systematic speech rehabilitation training at a later stage.