Individuals who with suicide behaviors pay more attention to negative signals than positive ones. However, it is unclear that whether this bias exists when suicide ideators perceive interpersonal stimuli (such as faces with emotion) and the underlying neural mechanism of the attention process. The present study aimed to examine the attentional bias toward emotional facial expressions by employing event-related potentials in a population with suicide ideation. Twenty-five undergraduates with suicide ideation (SI group) and sixteen undergraduates without suicide ideation (NSI group) participated in a modified dot-probe task. Compared to the NSI group, the SI group exhibited: (1) a longer mean reaction time to fearful faces; (2) a larger N1 component to fearful faces; (3) a larger N1 component to the location of sad faces, as well as to the opposite location of fearful faces and happy faces; and (4) a larger N1 component to the contralateral location of happy faces, whereas the NSI group elicited a larger N1 component to the ipsilateral location of happy faces. These results indicated that the SI group was more sensitive to negative emotions (fearful and sad faces) than positive emotions (happy faces), and the negative interpersonal stimuli in suicide ideators was processed at an early attention stage.