Crab is an important economic aquatic product in China and one of the main ingredients to induce allergic reaction. Therefore, it is extremely urgent to understand the species and epitopes of crab aquatic product allergens and explore effective techniques to mitigate crab allergenicity. The identification of crab aquatic product allergens and their antigenic epitopes is an important prerequisite to mitigate their allergenicity. Firstly, the isolation and identification of crab aquatic product allergens including tropomyosin, arginine kinase, sarcoplasmic calcium binding protein, triosephosphate isomerase, and filamin c and so on at home and abroad were summarized. The linear epitopes and conformational epitopes of crab aquatic product allergens analyzed by bioinformatics, phage display technology, and one bead and one compound technology were introduced. Secondly, modern processing methods, such as irradiation, ultrasound, Maillard reaction, enzymatic crosslinking, and microbial fermentation technologies, used to modify the allergen epitopes or destroy the structure of allergen protein to reduce the allergenicity of crab aquatic products were compared. Finally, the future research trend of crab aquatic product allergens was emphatically analyzed, and the relationship between the structure-activity of crab aquatic product allergens and allergenicity was proposed as the research difficulty in this field. The advantages and disadvantages of physical methods, chemical methods, and biological methods in mitigating the allergenicity of crab aquatic products were compared, and it was suggested that the combined processing methods should be developed in the future, so as to reduce the allergenicity to a greater extent and provide technical basis for the development of hypoallergenic crab food or biological products.