The N2pc component is a negative amplitude located at the back of the brain of the opposite side of the target stimulus, which is obtained by subtracting the ERP component of the same side of the target from the ERP component of the opposite side. The N2pc component is a well-characterized index of the covert deployment of visual attention. In previous studies, researchers have found that the types of the experimental task, distractor characteristics, cognitive load, and other factors affect the amplitude and latency of the N2pc component. In addition, the N2pc component as an index of the covert deployment of visual attention and Pd as an index of suppression of potentially distracting non-target items are widely used in visual attention-related research, and contribute to the study of the sustained attention process. In the future, the functional significance of N2pc and Pd components should be further explored, and they can also be applied to the study of attentional bias in special populations.