In order to work out the problem about power supply, microgrid systems based on wind-solar-seawater pumped storage can be built in isolated islands. The paper mainly does research on the comprehensive evaluation problem for day-ahead dispatch of off-grid islands about the structure. Firstly, considering economic, environmental, technical and reliability factors, a set of evaluation index system for day-ahead dispatch of island isolated microgrid is proposed. Secondly, the subjective weight of the intuitionistic fuzzy analytic hierarchy process method and the objective weight of the improved entropy weight method are integrated into the optimal weight by using the improved combination weighting model. Thirdly, a grey relational analysis-technique for order preference by similarity to ideal solution combination evaluation model based on the cooperative game and the improved cumulative prospect theory is constructed, and the effect of multiple decision-making psychology on the evaluation results is considered from the perspective of practical operation. Finally, taking EI Hierro island as an example, the feasibility and validity of the evaluation model can be verified, which is of guiding significance to the engineering practice of island microgrid.