This research aims to study the neural influence of conflict between brand and product performance on consumer decision. In the experiment, stimuli of products with brand and performance information were displayed randomly. 22 subjects need to decide whether to buy, while the event-related potentials (ERPs) were recorded. The stimuli were divided into four conditions based on the consistency of brand and performance (condition 1: well-known brand and superior performance; condition 2: well-known brand and inferior performance; condition 3: unknown brand and superior performance; condition 4: unknown brand and inferior performance). Thus, this paper focuses on two conflicting stimuli - conditions (2) and (3). Results showed that conditions (2) had higher purchase rate than condition (3). Although both conditions (2) and (3) have conflicting information, condition (2) evoked the higher amplitude of conflict-related N270 than condition (3) in the prefrontal regions, which meant the actual performance is different from the expectation established by the brand and evoke the conflict between the stimulus and the endogenous information. An essential component of ERPs, P300, was elicited in among all parietal and occipital regions in all conditions, but the P300 amplitude triggered by condition (3) was significantly larger than condition (2). The findings consisted with the results of N270. The findings explain the neurological and psychological activities when consumers are browsing products. Hence, N270 and P300 may be useful neural endogenous indicators to reflect the process of handling conflicts and evaluation of products in consumer decision.