The clinical diagnosis can detect the presence of brain disease once significant neuronal disruption has occurred. Early clinical detection of neuropsychological disorder lacks the unification standards. The aim of this study was to describe the neural mechanism of audiovisual interaction in healthy subjects by combining behavior-based methods (neuropsychological testing) and event-related potentials (ERP), and to provide a neural mechanism for early clinical detection. We designed the stimulus onset asynchrony (SOA) between sound and visual (-400 ms, -150 ms, 0 ms, 150 ms, 400 ms, visual only and sound only, each with equal probability, randomly in each trial), so that the subject could not find the cognitive rules connecting the two stimuli. The behavioral results showed that the responses to temporal congruency audiovisual (AV) stimuli were faster than those to unimodal visual(V) stimuli. The ERPs results showed audiovisual interaction elicited by irrelevant auditory(A) stimuli in a visual attention task. This interaction occurred at late stage around 220-240ms and 340-380ms.