At present，the common asphalt regenerant is used for treating the aged styrene-butadiene-styrene （SBS） modified asphalt in China，which fails to repair the SBS cross-networking structure，resulting in the poor regeneration effect of the aged SBS modified asphalt.In this study，a new reactive regenerator containing a structural repair agent，extractive oil，plasticizer，solubilizer，and a small amount of SBS was used to regenerate the aged SBS modified asphalt.The conventional properties and rheological properties of reclaimed SBS modified asphalt were studied by three index tests，Brookfield viscosity test，dynamic shear rheological test，and low temperature bending rheological test.Then，a fluorescence microscope and infrared spectrometer were used to study the regeneration mechanism of the reclaimed SBS modified asphalt.The results show that the conventional properties of the aged SBS modified asphalt can be restored after the addition of the reactive regenerant，and the regenerant content for achieving the optimal conventional properties of the reclaimed SBS modified asphalt is 10%.Under the optimal regenerant content，the conventional property indexes of the reclaimed SBS modified asphalt meet the technical requirements of Class I-D SBS modified asphalt in the Technical Specifications for Construction of Highway Asphalt Pavements （JTG F 40—2004）.After the aged SBS modified asphalt is regenerated，the SBS particles increase significantly and are distributed evenly，and the cross-networking structure is restored to a certain extent.The epoxy group in the regenerant polymerizes with the carboxyl group in the aged SBS modified asphalt to generate ester compounds and connect the b roken SBS molecular chains.