The invention provides a water tank wire drawing unit and a wire drawing process, and belongs to the technical field of wire drawing. The water tank wire drawing unit comprises a wire inlet mold box, a box body and a wire outlet mold box communicated in sequence; a spraying device and a wire drawing mold are arranged in the box body; a polishing device for polishing a metal cable is arranged between the wire drawing mold and the wire outlet mold box; a wire collecting device is arranged on one side, far from the box body, of the wire outlet mold box; and the metal cable is collected by the wire collecting device after passing through the wire inlet mold box, a driving tower wheel, a driven tower wheel, the polishing device and the wire outlet mold box in sequence. The water tank wire drawing unit and the wire drawing process adopt the structure of added polishing device, can effectively reduce the surface roughness of the metal cable, improve the quality of the drawn metal cable, enrich and intensify functions of a wire drawing machine, optimize the wire drawing effect on the metal cable, and make up defects in the prior art.