Abstract: In order to explore the application of sewage sludge in road engineering, this paper prepares artificial aggregate of domestic sewage sludge and applies it to asphalt mixture. Firstly, the optimum preparation process of artificial aggregate of sewage sludge is determined by orthogonal tests, and its physical properties are tested. Then its mineral composition and microstructure are then studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). Finally, the natural stone is replaced at a replacement rate of 30% to study the effect of sludge aggregate on the road performance of asphalt mixture. The results show that, under the optimum preparation process, the compressive strength of sludge aggregate is 29.47 MPa, which is lower than that of a natural stone. The water absorption rate is 0.26% and the apparent density is 2.64/cm3. There is a smooth enamel layer on the surface of the sludge aggregate, and the compactness of the green body is good, but the internal mineral crystal arrangement is scattered. Compared with AC-13 asphalt mixture, the sludge aggregate asphalt mixture has better high-temperature stability, but slightly lower low-temperature performance and water stability. The research results can promote the reuse of sewage sludge and the development of asphalt mixture.