Spices have been widely used in the food industry and home cooking, which significantly improve the sensory, physical, and chemical properties of food, such as aroma and color, and shelf life. There are more than 150 known natural spices in the world. Although the effects of natural spices on food flavor and quality have been reported in a few cases, the mechanism of action of natural spices is still not deep enough or systematic enough. This review summarizes the classification, characteristics, and functions of spices and discusses their application in aquatic products. The various functional properties of flavors can satisfy the needs of the aquatic products processing industry, such as flavor, deodorization, antimicrobial, and antioxidant. This review provides theoretical support for the comprehensive utilization of natural spices and the quality improvement of aquatic products.