The invention relates to a building technology for a pile leg of a self-elevating wind power vessel. The building technology mainly comprises the following steps that cylinders are rolled, wherein rolling is carried out on the two ends, the middle part is rolled after the two ends are rolled in place, rolling is carried out in place again, longitudinal seam welding is carried out after positioned welding, and final roundness restoration is carried out; the cylinders are welded, wherein the cylinders are matched, an assembling machine is used for assembling, positioning welding is carried out, and finally welding is carried out; pre-assembling is carried out in a workshop, wherein the overall linearity of a reference section, the gap and the alignment tolerance are adjusted, technological flanges are assembled and welded in place, and the cross central line, the height reference line and the central line of a bolt hole are marked out on the reference section; bolt holes are cut, wherein an upper section and a lower section are rotated to the position of a saddle-shaped cutting machine, the central line of the pile leg is adjusted to be parallel to a track of the saddle-shaped cutting machine, and cutting is carried out according to the marked lines. The building technology has the advantages that various building requirements of the pile leg can be ensured, meanwhile, the building efficiency can be improved, and the building cost can be reduced.