Extracorporeal prestressing technology is mainly used in bridges and other structural forms of construction, with the structural performance of extracorporeal prestressing, the corrosion problem of extracorporeal prestressing steel cables, the anchorage performance of the anchorage, fatigue resistance, and construction process simplicity and reduce the cost of the project and so on the various aspects of the problems are solved constantly, promote the development of extracorporeal prestressing in concrete structures. ovm.t15-25 extracorporeal prestressing system is a kind of single OVM.T15-25 extracorporeal prestressing system is a kind of single cable-exchange extracorporeal prestressing system. This paper talks about the application of OVM.T15-25 extracorporeal prestressing system in the project by combining the construction process of prefabricated suspension assembly of 75m span segmental continuous box girder for the superstructure of Sutong Bridge B2.