Tie arch bridges were built in large numbers in China in the 1990s, and many of them have to be replaced due to serious corrosion of the ties. Ful River Bridge in Mianyang City is a (46+202+46)m swallow type bollard arch bridge, the length of the bollard anchorage section is long and the bollard cannot be replaced directly. Taking the bollard replacement project of this bridge as an example, the key technologies of structural system conversion, temporary bollard and temporary support system setting of bollard replacement project were studied, and the construction points of bollard replacement project were introduced for the reference of similar bridge projects for reinforcement and maintenance.