Abstract:The common steel formwork used in the traditional box girder prefabrication requires coordination of manpower and machinery during the assembly process, which limits the construction efficiency. With the support of prefabricated bridge technology, a higher automatic assembly line based on moving hydraulic steel formwork and prefabrication technology is established. The formwork can be quickly transferred and installed through the rail system, which can improve the prefabrication efficiency of box girder. The example of the reconstruction and extension project of Nanjing urban area is taken in this paper to discusse mainly the application of moving hydraulic steel formwork in the precast construction of small box girder and to analyze its function and applicability in the precast construction of modern box girder.