Abstract: The coaxiality of shaft holes of large structural parts directly affects the rotary accuracy of the equipment and the service life of the bearings. Which is also a difficult problem to solve in the production of enterprise. The outer ring body of the swaying platform was manufactured in segments in the factory, with a reserved machining allowance for the shaft holes. The segments were scored on the template platform as a marking line for on-site butt welding. Each segment was annealed in the heating furnace to relieve stress. At the installation site, each segment was assembled and formed by welding, and ceramic sheets were used to heat and remove welding stress. The process route of laser tracker measurement and boring machining was adopted to achieve the coaxiality of large-span shaft holes of 0.4 mm. Practice has proved that the processing technology has good applicability to the processing of shaft holes of similar products.