Abstract: Human beings have been facing numerous emergencies which could threaten their property or even their lives in all ages. In order to learn how people respond to the emergencies like earthquakes and fire disasters, a two-stage simulation considering people?s rational thinking and irrational thinking was conducted. Results show that people?s irrational thinking, like the herd effect, could exaggerate people?s behavior of conformity, and it changes the spatial features that stronger herd effect leads to higher cohesion level. It is also worth mentioning that crowd response of condition of smaller population is harder to predict because of its instability, and the response of the very first part of people who make decisions could make great changes to the whole crowd?s response. These results could give some enlightenment on the evacuation instruction during emergencies and future research works.