In order to explore the road performance of rubber-and-plastic-alloy-modified asphalt mixture, the rubber-and-plastic is prepared from waste tire rubber and powder and waste plastic by precision mixer, and used to modify the matrix asphalt and mixture.The molding parameters of AC-13 and SMA-13 rubber-and-plastic-alloy-modified asphalt mixture are determined by orthogonal test. The road performances of rubber-and-plastic-alloy-modified asphalt mixture and waste-tire-rubber-and-powder-modified asphalt mixture are compared by rutting test, immersion marshall test, freeze-thaw splitting test and beam bending test. The results show that the molding parameters of AC-13 rubber-and-plastic-alloy-modified asphalt mixture are asphalt to aggregate ratio 4.8%, mixing temperature 180 ℃ and compaction temperature 165 ℃, and the molding parameters of SMA-13 rubber-and-plastic-alloy-modified asphalt mixture are asphalt to aggregate ratio 6.1%, mixing temperature 185 ℃ and compaction temperature 170 ℃. Compared with waste-tire-rubber-and-powder-modified asphalt mixture, rubber-and-plastic-alloy-modificd asphalt mixture has better high-temperature stability and water stability, but poor low-temperature crack resistance.