Tropomyosin (TM) was reported to be a supercoil allergen of shellfish. However, little information is available about its link between structure and allergenicity. In this study, the subunit of TM (α-TM) and supercoil of TM (α-TM) were identified from . α-TM showed higher immunoreactivity than α-TM. Meanwhile, seven linear epitopes in α-TM and α-TM were verified, and two conformational epitopes in α-TM were predicted. The physicochemical properties and chemical bond assays confirmed the existence of the disulfide bond in α-TM. According to spectroscopy and hydrophobicity analysis, α-TM showed higher α-helix features and blueshift of the fluorescence intensity peak compared with those of α-TM. The structure analysis revealed the possibility of conformational epitopes in α-TM, which could explain the immunoreactivity differences between α-TM and α-TM further. These results improved the understanding of TM, which lay the foundation for the food processing of abalone.