The technology of Human Machine Interface (HMI) mainly investigate about how to use machines in a more humanized way so that the communication between human and the machine could become more harmonic and natural. Previous studies indicate that there is an integration area in the human brain for audiovisual information processing. Although machines also possess mechanism for audiovisual processing, there is shortage of audiovisual information integration. And to solve this issue, the prerequisite is to make clear what kinds of cognitive processing characteristics do humans have. In this current Event-Related Potentials (ERPs) study, we adopted a left-and-right-separated sensory modality method to investigate the characteristics of human audiovisual information processing. The results showed that the main audiovisual interactions were found in frontal-central scalp sites around 80-100ms during the early stage and 280-300ms during the later stage of processing. This study provides foundation for understanding the information processing characteristic of human cognitive system and for the future machine humanization.