Abstract: In recent years, urban environmental risk problems caused by high-risk industries have been widely concerned. Urban environmental risk source classification is an important issue for urban environmental emergency management and guarantee of urban environmental safety. According to the environmental risk system theory and comprehensively considering the risk source, the accident spreading, the controlling ways and the environmental receptors, a classification evaluation index system based on the amount of environmental risk substances, the production process and risk control technical levels, and the sensitivity of environmental risk receptors was set up. The grade evaluation matrix of risk sources was established. The urban environmental risk sources were classified into 3 grades, i.e. high risk sources, ordinary risk sources and low risk sources. With Shanghai city as the case study area, the identification and classification of the environmental risk sources were conducted in 882 key enterprises in 17 districts. The results showed that there were 151 high risk sources and 161 ordinary risk sources, accounting for 17.1% and 18.3% of all the evaluated enterprises, respectively. Finally, the risk prevention and control countermeasures were proposed for the main districts, such as Jinshan District, Baoshan District and Minhang District.