Twomatrix asphalt binders were selected and mixed with Sasobit in different proportion to prepare warm mix asphalt binders.The dynamic shear rheometer tests were conducted,and the microstructures were characterized.Test results indicate that both of the rutting factor G*/sinδand fatigue factor G*sinδexponentially decrease with the increasing temperature but linearly increase with the increasing Sasobit dosage.The four chemical components test,infrared spectrum test and nuclear magnetic resonance test were also conducted to characterize the microstructure.The test results indicate that the four contents of chemical componentsare slightly changed after adding Sasobit into matrix asphalt binder,there is no chemical reactionbut similar physical dissolution between Sasobit and asphalt.