Decision makers usually face decision-making difficulties on Pareto feasible solutions generated by reservoir multi-objective operation model. To solve this problem, visualization tool together with marginal benefit analysis and fuzzy optimization method were proposed for gradual optimization of feasible solution set. The results showed that, by using different analysis tools and decision methods, feasible solutions received visual representation meanwhile some of the decision preference information was integrated to obtain the satisfactory solutions for different decision-making demands. By using different decision methods, the number of alternative solutions was reduced gradually to make the problem less complex. This paper can provide some references for multi-objective solution selection problem for decision makers.