Patients with major depressive disorder(MDD)develop a negative cognitive bias,but how they respond to information in Chinese emotional words is unclear.Here we used a Stroop paradigm with subliminal Chinese emotional words to explore the event-related potential components of abnormal emotional processing in patients with MDD.The correct rate was similar in MDD and normal control groups,but MDD reaction time was longer than the normal controls,especially to the negative and neutral stimuli.In N270,repeated-measure analysis of variance demonstrated a significant main effect of the relation electrode and valence on peak amplitude and interactions between valence and electrode site.The peak amplitudes of the three kinds of words were different in the two groups(positive > negative > neutral).The topography of the difference waves indicated that the difference distributed in the frontal and left parietal-temporal sites across the scalp.In N400,there was a significant main effect of the relation electrode and valence on peak amplitude,and the latency showed a main effect of the electrode and an interaction between electrode and group.The amplitudes induced by type of words were significantly different from each other in both groups(positive > negative > neutral).The topography of the difference waves indicated that the effect of relation type was primarily at left and right frontal and central and left parietal-temporal regions.Both MDD patients and normal controls exhibited significant emotional Stroop effects during the processing of positive/negative Chinese emotional words.MDD patients showed interference in emotional stimuli in early cognitive processing that induced psychological resource intervention during late emotional information processing.