Tropomyosin (TM) has been determined as the major allergen in Oratosquilla oratoria. However, little information is available about its antigenic epitopes and cross-reactivity. In this study, recombinant TM was obtained through genetic engineering and its IgG-/IgE-binding activity was similar to native TM. Subsequently, four T-cell epitopes were identified by using bioinformatics technology combined with CD4+ T-cell proliferation assay, and seven B-cell epitopes were identified by bioinformatics technology combined with serological assay. Moreover, dot blot analysis showed that TM had cross-reactivity among O. oratoria and other shellfish by using IgE polycolonal antibody from sera of shrimp-sensitive individuals or O. oratoria TM-immunized mice. Interestingly, three T-cell epitopes (AA4-24, AA194-212, and AA221-243) and four B-cell epitopes (AA85-100, AA121-138, AA209-233, and AA242-259) of TM in O. oratoria were conserved between O. oratoria and other shellfish, which may be the main reason for the cross-reactivity between them. In summary, these findings could serve for the diagnosis and prevention of shrimp allergy.