The invention discloses an ASA/PVC co-extrusion ultra-weather resisting colorful rainwater pipeline special for outdoor rainwater drainage. The traditional VPC rainwater pipelines are white, and are hard to be harmonized with the appearance of a building or be applied to western high altitude areas. The pipeline consists of an internal layer and an external layer, and is characterized in that the external layer is made of an ASA modified material, and comprises the following compositions: acrylonitrile, styrene, acrylic rubber terpolymer, complex pigment, chlorinated polyethylene, stearic acid, calcium stearate, nanometer calcium carbonate, compounded lubricant, titanium pigment, UV absorbent and antioxidizer; the internal layer is prepared by the following compositions: polyvinyl chloride, chlorinated polyethylene, calcium stearate, titanium pigment, organic stabilizer and PE wax. The external layer made of the ASA material has ultra-weather resistance and multiple colors to meet the requirement on the colorful pipeline in the market currently; and the internal layer greatly improves the toughness of the pipeline.