中文摘要：

研究表明，突变理论能够有效地描述解释具有突发性质的系统影响的优势，可作为风险评估的基础理论、模型与方法。从城市风险的基本要素包括经济支撑、社会协调、城市发展等三个方面主要因素，以此作为一级指标，构建了目标、变量和指标层在内的三层社会风险评估指标体系。通过2003～2012年四川省的相关数据，使用突变评估方法，得出了四川省城市社会风险的各因素单向风险和总风险的级别及其变动情况。

英文摘要：

Catastrophe theory has the advantages of having an effective description of the nature of the emergency system impacts, can be used as the basis of theories, models and methods of risk assessment. By analyzing the economic support, andsocial coordination, urban development of the city$ three aspects of social risk source of risk to build a three-tier risk assess-ment index system of social goals, variables and indicators layer. By the data from 2003 to 2011 in Siehuan Province, thecity of the social risks is assessed. At last, giving its level of risk and changes in circumstances.