Abstract: Jiaozhou bay is a ideal site for the study of bay ecosystem health monitoring since it is a typical coastal bay environment in China. The Guideline for the Assessment of Coastal Marine Ecosystem Health was applied to determine the environmental health condition of marine ecosystem basing on the data collected from Jiaozhou bay among 2019 to 2021. The findings indicated that the ecological system structure of Jiaozhou bay was in a sub-healthy state as a result of the biological density being higher than historical standards. Using historical monitoring data from recent decades, we also examined the developmental trajectory and current state of the marine natural environment and discussed the issues with evaluation techniques. The study demonstrated the necessity for specializing ecosystem environmental health assessment techniques for Jiaozhou bay.