Totheproblemsoflowannualaveragetemperatureandstrongultravioletradia-tion causing asphalt pavement aging easily in the western plateau area，nano-TiO₂ /MMT/SBR modifiers were chosen to prepare composite modified asphalt.The rheological proper-ties of modified asphalt before and after aging were evaluated by high-temperature dynamicshear， low-temperature bending beam and Brinell rotating viscosity tests.The mechanismof the modifiers was revealed by the infrared spectrum test.The results show that the hightemperature， low temperature and anti-aging properties of nano-TiO₂ /MMT/SBR compos-it e asphalt are improved.nano-TiO₂ /MMT and nano-TiO， /MMT/SBR samples have betteranti-aging properties than other combinations after analyzing the carbonyl index of modifiedasphalt.By analyzing the content of sulfoxide and sulfone functional groups， MMT can in-hibit sulfoxide group from being oxidized to sulfones.