Adding auditory white noise (WN) to the environment has been considered to be a promising way to enhance the memory performance of children with attention deficit/hyperactivity disorder (ADHD) but disrupt that of non-ADHD children. To explore the exact mechanism behind WN benefits, we did a bilateral color-memory task with different WN conditions. A bilateral color-square array was displayed on one display. Only one side colors were asked to be remembered in a trial. Our experiment found that the memory accuracy of left visual memory was improved with WN, especially when WN was displayed via left earphone at encoding and maintenance periods. However, the right visual memory showed a reduced performance tendency with WN. Thus, the WN affects left/right visual working memory in an opposite pattern. Using time-frequency analysis, we found an enhanced lower-alpha activity over the left occipitotemporal lobe. We conclude that the induced lower-alpha activity at the left occipitotemporal lobe might be helpful to inhibit information processing of left hemisphere.