The project’s investment risk evaluation system was built from six aspects of the naturalrisk,economic risk,political and social risk,technology risk,management risk and the bidding risk.In view of the defects and the insufficiency of common methods of risk assessment of water conservancyprojects,Grey AHP comprehensive risk evaluation model was used to evaluate.Firstly,determinationof the weights of evaluation indexes based on AHP,and then integrated assessment value was calculatedby grey theory,lastly to get the verdict.Moreover,water conservancy engineering project wasselected to verify the applicability of the model.The results show that the method can provide strongtheoretical basis for decision-making and risk management of investment risk in Water Conservancyand Hydropower Engineering project.