Social emotion is not only an issue within the scope of sociology and psychology，but also an important object of social psychology research. Study of social emotion is help for social mentality of monitoring and early warning. It will contribute to condensing public spirit and constructing a harmonious society. Our research of the characteristics and causes of formation of Beijing residents social emotion，is based on event-study analysis method. Besides，this paper studies the social emotion of measurement method，influencing factors and control measures etc..