Abstract: The panic induced by the sudden risk events is much more harmful than the risk events themselves. When risk events come, the extent of public rationality is an important foundation to cope with crisis. This article proposes the concept of public rationality, explains definition and its construct, and influence factors. Taking SARS as an example, this article also analysis the nature and characteristics of risk communization, and the possible ways and related conditions for risk communication to influence public rationality. This article provides the theory foundation to make an inclusion on SARS risk crisis, to study the psychological system in coping with risk events in order to promote the research and practice in risk communication field.

Key words: SARS, risk communication, public rationality