Large-scale facilities now are highly diversified and complicated in Japan. Therefore, chemical plant operators cannot grasp the overall situation in emergency. Human error was piled up the mechanical failure caused unexpected accidents. It becomes more important to perform of the “risk assessment” which is assumed accidents and causes. In this paper we propose to adopt of the philosophy of HAZOP analysis to the system. Accidents often happen in non-steady situation due to human factors. Operators cannot control enough when the plant conditions are changed depending on time and operation. This study shows the system linked with dynamic simulator for chemical plant. Initial condition for simulation and basal condition for operation should be set to the system, then preprocessor automatically generate accident case examples. Using the example data, accident solver operate dynamic plant simulator. Simulation results show fault propagation scenarios. Post processor of the system can analyze fault propagation scenarios. This system has been designed to support chemical plant operators by predicting accident cases on dynamic simulator. To convey accurately indication information of the risk, it is useful to recognize hazard identification.