Objective：To analyze epidemiological characteristics and trend of public health emergencies occurred in Chongqing during 2005-2011 and to provide scientific basis for effective pre－vention and control. Methods：Data of all public health emer－gencies occurred in Chongqing during 2005-2011 extracting from national information management system of public health emergency report in Chongqing Centers for Diseases Prevention and Control were collected. Data were analyzed using descriptive epidemiologic method. Results：A total of 2 193 events of public health emergencies were reported，including infectious diseases（2 011 events，91.7%），food and occupation poisoning（50 events，2.28%），mass unexplained diseases（13 events，0.60%），and other events that seriously affect public health（119 events，5.44%）. There were 54 938 events and 167 deaths caused by these events. Number of reported events in 2009 were the highest（727 events，33.15%），with seasonal peak from April to June. Geographically speaking，number of reported events in one hour economic circle was the highest（1 206 events，54.99%），followed by northeast wing（688 events，31.37%） and southeast wing（299 events，13.63%）. Re－gionally speaking，number of reported events in Kaixian district was the highest（190 events，8.66%） and Shuangqiao district was the lowest（3 events，16.05%）. Events occurred mainly in the school（1 769 events，80.67%），especially in township primary school（802 events，45.34%） and township middle school（284 events，16.05%）. Conclusions：Major public health emergencies occurred in Chongqing is infectious diseases，most of which occurred in schools and we should strengthen the prevention and monitoring.