Multi-touch is a kind of emerging technology in human computer interaction area. It does not only provide a more natural and intuitive interaction, but also allows multi users simultaneously to manipulate on the same display. Therefore, it usually would be suitable to be represented in the form of the large display in the public space. Furthermore, most of the research issues in the large and public display usually focused on the social network and the human behavior. However, few researches of the multi-touch area were mentioned about the issue, hence, in this study we built up a 100-inch multi-touch display to observe the human behavior through 6 cameras in the public space with a developed 'Photo Dig' interface for the use's manipulation. Finally, the five stages and three levels of the user interactive behavior model are proposed.