Objective To establish and improve the food composition database of He’nan Province， the nutritional components of fish， shrimp， crab， and shellfish in He’nan province were analyzed.Methods The water， ash， protein， fat， carbohydrate， total nitrogen， carbohydrate， multivitamins， and essential minerals of fish and crab from restaurants and supermarkets from December 2017 to December 2020 were determined.Results The water and ash contents were basically the same. Carbohydrate was not detected except in fried food. The energy content of crab was higher than that of fish and shrimp. The energy， protein， total nitrogen， and fat contents of fried fish were higher than those of fresh fish. The total amount of fatty acids in fish， shrimp， crab， and shellfish was normal； EPA and DHA were the major components. The highest content of DHA was observed in squid （0.209 g/100 g）， pasha （0.181 g/100 g）， and cod （0.153 g/100 g）， and the highest content of EPA was observed in crab roe （1.07 g/100 g）， small yellow croaker （0.38 g/100 g）， and golden carp （0.297 g/100 g）. All the amino acids were detected in fish， 90% in shrimp， crab， and shellfish， and the content of amino acids in crab roe was higher.Conclusion Flavoring and cooking oil influenced the food composition in the cooking process of fish， shrimp， and crab products. The content of monounsaturated fatty acids was positively correlated with the total fat content in fresh fish. Fish and crab had higher contents of monounsaturated fatty acids， and shrimp had the recommended proportion.