Shellfish, including crustaceans and molluscs, have high nutritional value and economic value. As a big producer and consumer of shellfish, food allergies caused by eating shellfish are increasing in China. The identified shellfish allergens include tropomyosin, arginine kinase, sarcoplasmic-calcium-binding protein, myosin light chain, etc. Epitope is the molecular basis for the action of allergens. To identify antigenic epitopes of different allergens is the key to further analysis of their sensitization and cross-reactivity, and is also an important prerequisite for directional reduction of sensitization. In this paper, the research progress of shellfish allergen species, antigenic epitopes, cross-reactivity and processing reduction allergen sensitization are introduced.