In order to meet the span requirements of bridges over the Yellow River and reduce the interference of temporary construction facilities on flood discharge from the Yellow River,the Linyi Yellow River Bridge was studied.The main bridge adopted a continuous long-cantilever closed steel box composite girder of (112 + 28 × 128 + 120) m and was divided into two parts,with the maximum length of the parts being 1 912 m.The steel box composite girder was constructed by incremental launching method without temporary piers,and the bridge deck was installed after the closed steel box girder was in place.The installation sequence of the bridge deck was from the positive bending moment area in the middle of the span to the negative bending moment area at the fulcrum.The research focused on three key technical issues:optimization measures of mechanical properties in the negative bending moment area of the composite girder,fatigue resistance design of diagonal braces,and optimization design of wind resistance of a 2.5 m-high acoustic barrier.The results show that the compression stress on the bottom plate of the steel box girder and the crack width of the bridge deck can be reduced by using the composite structure in the negative bending moment area.The optimization effect of externally tensioned prestressed steel bundles decreases gradually with the shrinkage and creep of concrete.The fatigue resistance of diagonal braces of square steel pipes with the same cross-sectional area is better than that of round steel pipes.The polygonal acoustic barrier can effectively suppress the vortex response of the main girder.