<p>Several models for estuarine physical processes and biogeochemistry have been developed over last decades. One of the most comprehensive coupled model systems, Finite Volume Community Coastal Model (FVCOM) coupled with European Regional Seas Ecosystem Model (ERSEM) through the Framework for Aquatic Biogeochemical Models (FABM) has been implemented to a high resolution coastal East China Sea (ECS), which encompassed complex coastal zone and part of continental shelf. Physical model was assessed by traditional univariate comparisons, while a rigorous model skill assessment was conducted for coupled biological model. The model system's ability to reproduce major characteristics both in physical and biological environments was evaluated. The roles of physical, chemical and environmental parameters on the biogeochemistry of the ECS were extensively studied. This work could form a significant basis for future work, e.g. the response of biogeochemical flux to physical mechanism.</p>