The risks faced in the construction of south-to-north water transfer project in northern Shandong are concluded organization risk, economical and management risk, engineering environmental risk and technology risk. Based on grey system theory and AHP method, the paper set up a grey hierarchy evaluation model to assess quantitatively the construction risk of south-to-north water transfer project in northern Shandong. The purpose is to make managers have a clear understanding of the risk degree and take countermeasures to minimize the accident loss and ensure the smooth progress of construction.