Background: Accumulating evidence substantiates the adverse impact of psychological maltreatment on children's emotion regulation. Nevertheless, scant research has explored the relationship between psychological maltreatment and automatic emotion regulation (AER), along with its underlying neural mechanisms. Objective: This study aims to investigate whether psychological maltreatment compromises children's AER and its associated electrophysiological mechanisms using the event-related potential (ERP) technique. Methods: Forty children (M[subscript age] = 10.10 years, SD = 1.24, 21 girls) completed an implicit emotional Go/NoGo task while the electroencephalograph (EEG) signals were recorded and then finished the self-report scale of psychological maltreatment. Results: The ERP results demonstrated that NoGo-P3 amplitudes represented the automatic response inhibition towards negative and positive emotions. Moreover, NoGo-P3 amplitudes elicited by viewing negative faces and positive faces were negatively correlated with psychological maltreatment. Conclusion: This suggests that psychological maltreatment may impair children's automatic response inhibition. Our observations contribute to a deeper understanding of the neural mechanisms that underlie the negative association between psychological maltreatment and AER in children.