The invention relates to the field of pitch and bituminous concrete, in particular to a construction method of rubber-plastic-alloy-modified bituminous concrete. The construction method comprises thesteps of (1) mixing rubber-plastic-alloy-modified bituminous concrete, namely adopting wet-method mixing or dry-method mixing; (2) paving an upper-middle surface layer of a pavement with the mixed rubber-plastic-alloy-modified bituminous concrete, and rolling the pavement; and (3) making the pavement carry traffic after maintaining the rolled pavement. By means of the method, the pitch modifier kind is broadened, the construction method is simple and convenient, the technology is simplified, the modification cost is reduced, no special equipment is needed, compared with rubber powder-modifiedpitch, the rubber-plastic-alloy-modified bituminous concrete obtained through the rubber-plastic alloy wet-method construction technology can be transported over long distance, the storage stability is good, the performance can reach or even exceed the performance of traditional SBS I-D modified bituminous concrete, the high temperature performance is more outstanding, and the cost can be reducedby 10-20%; and the construction technology is simple, a production process of modified pitch is omitted, and the construction quality and the construction efficiency are obviously improved.