Abstract: Based on analysis of status and characteristics of the marine ecosystem of Liyahshan Oyster Reef Special Marine Reserve of Haiman, an ecosystem health assessment index system for special marine reserves is constructed consisting of 24 indices covering three aspects, i.e. environment, structure and stability. Health of ecosystem of the reserve was assessed and analyzed by comparison, using the entropy comprehensive index model and entropy fuzzy comprehensive evaluation model. The former indicates that the ecosystem is turning from the state of health to that of sub-health, while the latter shows that the ecosystem is still quite healthy. As the latter may reflect health conditions of the various ecological elements of the reserve and yield conclusions closer to the status quo of reserve, it is more suitable for use in health assessment of marine reserves.