The aim of this research was to assess heat induced changes of the potential allergenicity and the structure of ovotransferrin (OVT). Changes in conformational structure of OVT were characterised by circular dichroism (CD) spectroscopy, ultraviolet (UV) absorption spectroscopy and fluorescence spectroscopy. A reversible unfolding structure was found at 55–60 C, followed by the loss of secondary structure at 70–80 C. Cleavage and rearrangements of disulphide bonds occurred when heated above 80 C. The indirect enzyme-linked immunosorbent assay (ELISA) of heat-treated OVT with egg allergic patients’ sera and specific rabbit polyclonal antibodies against native OVT showed that the potential allergenicity of OVT correlated well with the structural changes. Allergenicity increased with the unfolding of its structure, and decreased with the cleavage of disulphide bonds and the rearrangements of disulphide bonds. The results suggested that conformational changes of OVT induced by heat treatment significantly influenced the allergenicity of OVT, and the potential allergenicity of heated OVT is related to individual patient characteristics.