Recently, international plants construction markets are expending. Specially, oil/gas plants constructions in Middle-East are booming. However, international plants construction projects are high risky. So a risk assessments and managements methodology for international plants construction is needed. In this study, the risk assessment methodology for international plants construction is proposed on the basis of the literature review in the international construction risk assessment methods and the knowledge of experts explored by interview. In addition, case study in Middle East was applied for reviewing these risk assessments and managements methodology for international plants construction.