Abstract: The Dynamic Shear Rheometer (DSR) and Atomic Force Microscope (AFM) were utilized to test matrix asphalt and rubber-modified asphalt before and after freeze-thaw cycles. The dynamic viscoelastic parameters and its microstructure had been compared and analyzed under different salt concentrations and cycle times, and three major indexes of two kinds of asphalt had also been tested before and after freeze-thaw cycles. The results show that storage modulus and rutting factor of matrix asphalt increase, and fatigue factor decreases, but rubber-modified asphalt has no significant change after freeze-thaw cycles, while freeze-thaw cycle increases the high temperature elastic property, but it decreases anti-fatigue ability of matrix asphalt greatly, and makes little influence on high temperature rheological properties of rubber-modified asphalt. AFM observations show that matrix asphalt appears "bee structures", which becomes bigger and longer after freeze-thaw cycles, but rubber-modified asphalt has no significant change, so rubber-modified asphalt used as pavement material has more advantage in north cold region.