Abstract: The diatomite-cellulose composite fiber (DCCF) is made from diatomite and cellulose fibers and prepared via specific surface treatment under high shearing conditions. The DCCF was used to modify the asphalt for pavement, then the high/low-temperature performance and temperature susceptibility of the modified asphalt were investigated experimentally. The results showed that these performances of the DCCF-modified asphalt are all improved obviously and will be the best if the modifier dosage is 0.5%. After the modification the penetration index increases by 2.43, the equivalent softening point increases by 7.7°C and the equivalent brittle point decreases by 16.8°C in comparison to the asphalt matrix without modification.