Abstract: Influenced by the changes in natural conditions and human activities, groundwater vulnerability assessment, focusing on the vulnerability evaluation inherent to the hydrogeology, has reached a new phase of integrated risk assessment by taking into account the pollution caused by human activities, its negative effects on water environment, as well as the index risk rank and risk importance of groundwater environment.To resolve the problems of the impreciseness, complex implementation and the real number, resulted from the existing approaches to quantitatively describe the risk grade and importance of groundwater environment system, a aggregative risk assessment method for groundwater environment system was established, using Stochastic Simulation and Triangular Fuzzy Numbers (ARA-SSTFN).Based on an overall consideration of the hydrogeology and human activity factors, the proposed model transforms the operations between triangular fuzzy numbers and its functions into the conventional operations of real numbers by using stochastic simulation methods to generate triangular numbers.The result shows that the ARA-SSTFN, expressed by the confidence intervals, provides more reliable information on the evaluation results than the current conventional approaches, and can reflect the actual conditions of the comprehensive risk assessment for groundwater environment system affected by various uncertain factors comprehensively.It is also indicated that the ARA-SSTFN has a clear concept, a simple implementation, and it is sufficiently general to be applicable to the comprehensive risk assessment in various resources and environment systems (e.g., water resources, water environments, and water disasters) as a result of comprehensive effects of many uncertain factors, such as randomness, fuzziness and inexact data.