Prefabrication and construction method of box girder in-situ pedestal

The invention particularly relates to a prefabrication and construction method of a box girder in-situ pedestal, which solves the problems that cast-in-place box girders are high in cost and slow in progress and engineering construction is affected. The prefabrication and construction method includes: a, surveying lofting, performing replacement and layered compaction, and backfilling and tampering the area around an abutment; b, erecting a formwork to concrete a concrete pedestal serving as a bottom form, reserving pull bar holes on the top of the pedestal, and casting a concrete foundation around the pedestal; c, tying tie bars to fasten the bottoms of the lateral forms, using support bars to adjust the top elevation of the lateral forms, using a cup-lock scaffold to reinforce the lateral forms, and placing adjustable jacks and square timber on the top of the scaffold; d, pre-stressing the lateral forms to eliminate non-elastic deformation of a foundation and the scaffold, and correcting elevation of the fo