According to the characteristics of real estate investment decision,the group AHP was applied and hierarchical assessment system was presented.The limited information and the plans were associated,which can avoid the subjectivity of the decision.Then the grey-relevant method was used to present a real estate investment decision method based on grey synthesis assessment.During quantifying the qualitative indexes,set-valued statistic analysis was introduced,which reduced the uncertainty of the real estate investment assessment.A case shows that the method is feasible and valid.