After a cochlear implant is successfully implanted in a hearing-impaired child, the sound signal is processed by the cochlea into electrical stimulation via the auditory nerve and transmitted to the child’s brain for analysis, enabling the hearing-impaired child to hear again and learn language at the same time. However, there are great individual differences in the results of cochlear implantation. For children with poor post-operative rehabilitation results, after ruling out problems with the cochlea itself, Zheng Yiqing’s team from the Department of Otolaryngology at Sun Yat-sen Memorial Hospital of Sun Yat-sen University conducted a series of studies on this issue, including an EEG examination of the child’s brain to grasp the pattern of EEG development, and found that auditory function is related to the processing ability of the center. In general, the factors that affect the central processing ability are as follows: firstly, it is necessary to ensure that there is effective information input, and the commissioning of the cochlear implant determines whether it is in optimal working condition; secondly, different rehabilitation training methods affect the way the brain processes sound; and finally, there is the issue of the processing ability of the brain itself, and the latter is related to the ability to remodel the nerves in the auditory center. Through EEG, it is possible to find out which of these components is wrong in a child who is not recovering well. Many children who do not recover well may achieve good recovery after targeted treatment. If the EEG detects a problem with the child’s central processing ability, a weak response to sound, an EEG response that should occur but does not, or a response that is not at the level it should be, after the cochlear implant has been adjusted to work optimally, we will take the following two steps. If there is a problem with the method of rehabilitation, we will improve the method of speech training. If there is a problem with the central development itself, we will look for the cause, and for children with poor neurological development, we will provide pharmacological intervention. Although there is a controversy about whether or not to let the child look at the mouth. Our study found that vision is one of the key factors affecting the outcome of postoperative rehabilitation in children. Improper application of vision can affect the rehabilitation outcome, while proper application of vision can help auditory rehabilitation. Early visualization is a condition that helps children with cochlear implants learn to pronounce words correctly, but some children with cochlear implants rely excessively on lip reading, resulting in their auditory processing brain areas being occupied by visual processing. We can use EEG testing to understand the impact of visual compensation on auditory function. For example, a child who had cochlear implant surgery at the age of 4 had a very good recovery at the age of 6, but later entered a normal elementary school and developed a habit of relying on lip reading to communicate. We monitored the child’s visual compensation by reducing his visual dependence, increasing auditory stimulation, and performing several EEGs during the period. In another child who was admitted to our hospital after cochlear implantation, the parents themselves provided post-operative speech training to the child, but one year later, the child’s pronunciation was still very unclear for unknown reasons. We found that the child’s visual activation of the auditory area was weak through EEG, and further communication revealed that the child’s parents had never combined speech training with oral speech during the training period. After six months of rehabilitation by looking at the mouth and lips under the guidance of Director Zheng, the progress of pronunciation was very obvious. From these two cases, we concluded that the child’s visual compensation can be assessed in time by EEG. If it is found that the visual activation of auditory area is more obvious and the overall recovery effect is not obvious, rehabilitation training can be carried out by reducing the child’s visual dependence and enhancing auditory stimulation. If the child’s recovery is not obvious after avoiding vision and the EEG reveals that visual activation is too weak, training can be combined with combined audiovisual stimulation. EEG provides a new monitoring window for children with cochlear implants, allowing early detection of problems, early prediction, and timely intervention to improve the rehabilitation outcome of children with cochlear implants.