Abstract: The present application disclosures a double production line and a rapid prefabrication process of a segmental beam. The double production line including two production machine and a track system provided on the construction ground; the production machine includes a fixed end mold, two side molds, a bottom mold trolley, a middle internal mold trolley and two side internal mold trolley; two side molds are positioned on two sides of the fixed end mold respectively, the fixed end mold and two side molds together define a pouring position with an end opening, two openings of the pouring position are arranged facing each other; the track system includes a transverse track and a longitudinal track communicated with each other, two pouring positions are both positioned in the extension path of the transverse track, and the longitudinal track is positioned between two pouring positions.