Abstract: The impact of food nutrients on human health depends primarily on the digestion process in the gastrointestinal tract. The in vitro digestion model can simulate the digestive processes in vivo conditions integrally. It has the advantages of reproducibility, simplicity and universality. In vitro digestion can not only forecast the relationship among food composition, structure and digestive characteristics, but also calculate the bioavailability of food components and the impact of digestive metabolites on body health, so it is an important way to research nutrients in food. In vitro digestion has been widely used in the study of nutritional active substances in aquatic products. This article reviews the current situation of the in vitro digestion model and states the advantages and disadvantages of static and dynamic models and their applications in detail. It systematically summarizes the application of in vitro digestion in the study of nutritional active substances in aquatic products, including research on the digestibility of protein, the stability of bioactive peptides, the digestive and fermentation characteristics of polysaccharides, and the oxidation stability of lipid. In addition, suggestions for the limitations and optimization of the in vitro digestion model have been provided. It is expected to be useful in the future for its application in marine biomedicine, marine functional food and other fields.