The existing prestressed concrete continuous box girder bridge often has various bearing diseases after a certain period of operation, which seriously affects the normal use of the bridge. Taking the replacement of the support of a large-span railway continuous beam bridge in Guangzhou as the background, a segmented and step-by-step lifting scheme is adopted to meet the construction requirements of the railway near the business line. According to the design of the lifting plan, finite element software Midas Civil was used for calculation and analysis. Considering uninterrupted traffic conditions, the support reaction forces of each support and the stress state of the bridge structure under the lifting height of 3mm were calculated, providing a theoretical basis for lifting construction. At the same time, the number of jacks should be reasonably arranged to accumulate experience for large-tonnage lifting construction and provide reference for the replacement of bearings for similar bridges in the future.