An analysis on chemically-grafted polyethylenes as asphalt modifiers was carried out. Results show that the softening point of asphalt increased, while the penetration degree decreased in blends prepared with grafted polyethylene. The phase distributions of micrographs from fluorescence microscopy show that non-grafted polyethylene polymers were not readily miscible with asphalt. Rheological tests indicate that most of asphalt blends exhibit improved performance at higher temperature with grafted polyethylene such as enhancing rutting resistance, flow activation energy and superior time-temperature-dependent response as compared to the reference polyethylene blends.