Vision and auditory are the primary source of information for people to obtain passage, reading, calculating, thinking and other cognitive processes are dependent children involved in sustained attention, sustained attention of many cognitive processes is to ensure the smooth conduct of children visual, auditory channel characteristics and sustained attention neural mechanisms are not clear.In this study, children aged 12 to 14 were tested using the method of event-related potentials, CNV using an experimental paradigm, subjects were investigated visual and auditory channel of sustained attention in the process.The results showed that children aged 12 to 14 to keep the capacity is in rapid development period, from behavioral data, visual reaction channel relative to the auditory channel significantly delayed, visual channel P300 amplitude was significantly greater than the auditory channel.The results suggest that the visual channel needs to pay more cognitive resources. From the late CNV component, the average volatility of the auditory channel is significantly greater than the visual channel, auditory channel of sustained attention capacity significantly better than the visual channel.