Aiming at decreasing the flow corrosion failure happened frequently in refining system, considering the requirements of onsite system reliability and security, on the basis of enterprise's existing information system, a real-time expert diagnostic and supervision system for flow corrosion condition based on Aspen Plus technology is developed. The system uses object-oriented design principles, with .NET as the development platform and MySQL as the backend database. Using the ActiveX technology of Visual Basic (VB), and Aspen Plus, process simulation model is connected with the system. Windows Communication Foundation (WCF) and .Net Remoting techniques are used for data communication. This structure given previously can be applied to a variety of oil refining systems. An application instance in atmospheric overhead system has been developed, which can achieve the dynamic data monitoring, the query of historical data, guidance and measures of limiting alarm, with effective function in corrosion prevention and control.