The Longhai Railway Bridge on Daqing-Guangzhou expressway is 767.774m long. It is a prefabricated prestressed concrete continuous beam bridge with 6 bridges and 34 spans. It was completed and opened to traffic at the end of 2006. In 2017, the bridge was evaluated as class 4, and the main diseases were vertical cracks in the web of small box girder and transverse cracks in the bottom plate. The project is a railway related project, which is complex. It is the first time in Henan province that the external prestressing of steel anchor block is adopted to reinforce the precast small box girder. The construction scheme was observed and popularized in Gaofa group, forming a patent and jointly publishing a monograph.