Aiming at the nonlinear problem of regret value when regret theory is used to solve multi-attribute group decision making problems in hydraulic engineering, a multi-attribute group decision making method combined with grey correlation analysis method is proposed. Firstly, the regret theory was used to obtain the decision maker's perceived utility for each option and determine the regret decision matrix. Secondly, according to the nonlinear problem between regret values, the weight of attributes and the comprehensive regret value of each scheme were calculated by grey correlation analysis, and then the best scheme was obtained according to the ranking of the comprehensive regret value. Finally, the feasibility of the method was verified by case analysis. The results show that this method can solve the nonlinear characteristics and weight problems in regret theory, and make decision-making more reasonable when considering psychological factors.