Taking the construction of a 55m-span prestressed continuous constant cross-section box girder of an expressway bridge as an example,the construction of the 55m-span prestressed continuous constant cross-section box girder of this super-large expressway bridge is adopted.During the construction of simply-supported box girder in-situ cast-in-place by support method,support erection technology,support preloading technology and concrete casting method of box girder are used.The aim is to provide construction experience and guidance for similar projects.