Abstract: The dynamic mechanical analysis (DMA) method was adopted to study the viscoelastic properties of multiple recycled SBS modified bitumen． The recycling effect and the retention degree of unique viscoelasticity of SBS modified asphalt were evaluated by comparing the parameters such as complex modulus，phase angle，the va- riation of rutting factors，elastic recovery rate and unrecoverable creep compliance． The aging and regeneration processes were observed by fluorescence microscope． The results show that recycling effect of SBS modified asphalt is getting worse and the unique viscoelasticity of SBS modified asphalt is decreasing gradually with the increased times of asphalt aging and recycling． Multiple stress repeated creep (MSRC) tests show that the repeated recycled asphalt is more sensitive to the stress level，and the elastic recovery ability becomes worse and closer to the hard asphalt． Therefore，it is difficult to meet the MSCR classification standard suitable for SBS modified asphalt． Flu- orescence microscope was used to observe the aging and regeneration process． The images show that the SBS is poly- merized gradually during the aging process，and the compatibility become worse． The rejuvenating agent could on- ly supplement the decrease of the light component caused by the migration of the asphalt component during the aging process． However，the SBS modifier can't be redispersed． If SBS modified asphalt has been regenerated three times or more，and only rejuvenating agent can be used，then the recycled SBS modified asphalt can be used as hard asphalt． In oder to keep good road performance of modified asphalt pavement，the newly added modified asphalt should supplement old asphalt's loss of SBS viscoelastic characteristics． So customizing new modified as- phalt will become a technical approach．

Key words: SBS modified asphalt, DMA method, viscoelasticity, rejuvenating agent, aging