NOVELTY - Welding positioning process for conductor rail erection column of megawatt-wind turbines, comprises e.g.: rotating the rough positions of the middle lines of the two rows of erection columns (5) to the lowest position of the tower barrel; drawing the reference line (3); positioning the correction lines; fixing the erection columns of the stator and the rotor conductor rails; aligning the lowest point of the erection column to the lowest point of the tower barrel welding position; and welding the erection column, and detecting its straightness.    USE - The method is useful for welding positioning process for conductor rail erection column of megawatt-wind turbines.    ADVANTAGE - The method improves the accuracy and straightness of the conductor rail erection column in the tower barrel by positioning and welding, and thus ensures the product quality and shortens the production cycle.    DETAILED DESCRIPTION - Welding positioning process for conductor rail erection column of megawatt-wind turbines, comprises: (a) rotating the crude positions of the middle lines of the two rows of erection columns (5) to the lowest position of the tower barrel; (b) determining the midline between the stator and the rotor conductor rails on the tower barrel two ends flanges, using the center of the two flanges nearest the midline as a reference to draw the reference line (3), and using the same blunderbusses to punch on the inner diameter surface of the flanges, determining the vertical positions of the erection columns in the inner wall of the tower barrel according to the drawing size; (c) positioning the correction lines, using fixed bolts to fix the positioning frock on the reference hole of the flange, aligning the positioning points of the positioning frock to the reference lines, adjusting the nylon bolts to make the upper edge of the positioning frock vertical to the reference line, tightening the fixed bolts, using magnetic buttons to press one end of the two correction lines, pulling the correction lines straightly to the other end of the tower barrel, then using the magnetic buttons to fix the other end of the two correction lines, finishing the setting of the correction lines; (d) using the welding frock (2) to fix the erection columns of the stator and the rotor conductor rails; (e) aligning the lowest point of the erection column to the lowest point of the tower barrel welding position; (f) repeatedly adjusting the erection column according to the correction lines to make the center of the screwed hole of the erection columns below the correction lines, point welding positioning the erection column; (g) welding the erection column under the condition of not removing the welding frock, removing the welding frock after fully cooling the welding gaps; (h) using the correction lines again to redetect the straightness of the erection columns after removing the frocks on the erection columns, correcting the erection columns if askew; (i) drawing red counterpoint marks on the blunderbuss positions in the step (b) after finishing painting the tower barrel, guaranteeing the counterpoint marks on the companion flange being in the same straight line when lifting the tower barrel.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the welding fixture.    Welding fixture (2)    Reference line (3)    Erection columns (5)