Urban security is one of the important goals of urban development and management. As urban spaces become more and more complex and urban social and economic activities become increasingly diverse，the connotation of urban security has been expanded time and again. In addition to active monitoring，forecasting and prevention of natural disasters，municipal governments at all levels need to prevent and respond to fire，traffic accidents，major criminal cases and other human accidents，industrial accidents，engineering disasters，collapses and other technical disasters，attacks and environmental accidents. The study shows that the numbers of criminal cases，traffic accidents，deaths from traffic accidents and deaths in production accidents in China have been significantly reduced in recent years，as a result of effective urban safety management in these areas. However，there have been chemical incidents with a large number of casualties and frequent environmental pollution incidents such as soil pollution，water pollution and air pollution，which are new urban security issues brought about by the increase in the complexity of production activities. Deadly terrorist attacks in other countries are a cautionary warning to Chinese cities about the necessity to shore up their anti-terrorism measures.