The invention discloses a skid-mounted spiral submerged arc pipe welding unit. The skid-mounted spiral submerged arc pipe welding unit comprises an I-shaped steel frame base, two first supporting plates are arranged at the top end of the I-shaped steel frame base in a co-arranged mode, a strip steel winding frame is arranged between the two first supporting plates, the strip steel winding frame isrotationally connected with the first supporting plates through rotating shafts, strip steel is arranged on the strip steel winding frame, a flattening limiting plate is arranged on one side of the strip steel winding frame, and the flattening limiting plate is fixedly connected with the I-shaped steel frame base through a support. According to the skid-mounted spiral submerged arc pipe welding unit, a first electric telescopic rod and a welding seam laser tracker are arranged, the first electric telescopic rod cooperates with a second electric telescopic rod so that a welding gun can freelymove, then the welding gun can be aligned with a welding seam through the welding seam laser tracker, the precision and the quality of welding are guaranteed, a steel pipe is preformed in a pre-welding mode inside the steel pipe formed by the strip steel, then the formed steel pipe undergoes submerged arc finish welding, so that the characteristics of forming and the characteristics of welding arefully utilized.