In order to understand the contribution of asphalt components to thermoreversible aging, the extended bending beam rheometer (Ex-BBR) test, SARA fractions separation, and thermal analysis were performed on a series of asphalt binders from different sources. The results indicated that thermoreversible aging is not an inherent characteristic of asphalt, and some binders were not affected by thermoreversible aging. Grade loss caused by thermoreversible aging showed a high correlation with wax content in asphalt but had no apparent relationship with asphaltenes content and colloidal structure index used. Moreover, the thermal analysis results well explained the degree of thermoreversible aging in the asphalt binder. Finally, the endothermic peak and crystallites formed in asphalt binder could have resulted from the long side chains in naphthene aromatic molecules.