Renewable energy sources (RESs), particularly solar and wind energy, present a viable pathway for decarbonizing isolated microgrids (MGs). However, as the penetration of RESs increases, ensuring the optimal utilization of RESs while maintaining the system reliability poses significant challenges for isolated MGs. Therefore, a hierarchical coordination optimization method of the isolated electricity-hydrogen MG with high penetration of RESs is proposed to achieve low-carbon dispatching. The developed isolated electricity-hydrogen MG is an integrated system featuring hybrid battery-hydrogen energy storage, which encompasses three interconnected subsystems: an AC subsystem, a DC subsystem, and a hydrogen subsystem. The proposed method can be divided into two dispatch horizons: an annual horizon and a daily horizon. The annual horizon focuses on the inter-day energy dispatch, addressing hydrogen storage boundary conditions to solve seasonal energy mismatches. The daily horizon focuses on the day-ahead power dispatch to ensure the daily power balance of MG, taking into account the errors in annual estimated data. The effectiveness of the proposed method is validated through a series of case studies for an isolated electricity-hydrogen MG under varying penetrations of RESs and energy storage configurations. Simulation results show the promising potential of the proposed method in facilitating sustainable isolated electricity-hydrogen MGs.