Based on the lessons and experience from the country's fight against SARS, the paper analyzes the problems and shortcomings in its public health emergency reaction. It also describes the pubhc health systems set up in America, Britain and Japan in response to emergent events. With regard to the building up of a public health emergency system that conforms to the situation in China, the following proposals are put forward: (1)establishing effective command networks, such as setting up a national crisis management commission and formulating corresponding laws and regulations and crash programs; (2)establishing unimpeded information networks, such as setting up a national disease monitoring and reporting system and urban symptom monitoring systems; and (3)establishing tight prevention and treatment networks, with the network of prevention being composed of the headquarters, disease prevention and control institutions, medical institutions, health supervision institutions, experts commissions, and cooperation centers for tackling key problems in science and technology.