The different wind and solar output and load levels of island microgrids in different seasons and the lack of cross-seasonal long-term energy storage methods have led to the current large-scale abandonment of wind and solar energy and high carbon emissions in island microgrids. In order to improve the utilization rate of wind and solar energy and reduce carbon emissions, an island integrated energy microgrid including hydrogen energy storage system and seawater source heat pump is established. The objective function is to minimize the annualized cost, the abandoned wind rate and the carbon emissions. Taking the output of distributed power generation and power balance as constraints, the NSGA-III algorithm is used to optimize the capacity of each distributed generation source with multiple objectives, and the fuzzy membership function is used to select the solution with the highest comprehensive satisfaction. The superiority of the integrated energy microgrid is verified by the example and it provides a reference for the planning and construction of island microgrids in the future.