Abstract: Based on part of the fruit of research project named ARAIMS(industrial accident risk assessment system) which is carried out by EU and under the present research of pipeline risk assessment system, a new definition framework is established, that is risk = severity X vulnerability.The evaluation process divides regions around pipeline into a number of geographic units to assess the severity and vulnerability for each unit, and then calculates risk value.Pipeline failure threat and data interpolating method are adopted to evaluate the severity and vulnerability.and GIS spatial analysis and visualization technology are used to realize regional evaluation of risk and visualization.Combined with concrete cases, this paper introduces realization process of the risk assessment system on severity and specifies problems existed in application.