Abstract: In order to study the corrosion characteristics of the bearing parts of the steel plate girder bridge and its influence on the bearing capacity of the structure, the finite element model of bearing parts of steel plate girder bridge including the inner web, the outer web, the lower flange and the stiffening rib was established by taking the stiffening rib as the dividing line. The stress distribution before corrosion was analyzed, and the possible corrosion morphology was given by comparing the stress distribution range with the statistical results of the actual bearing corrosion investigation. On this basis, the influence of corrosion morphology, corrosion area and corrosion depth of bearing parts on the bearing capacity of the structure was studied, and the most unfavorable corrosion conditions were determined. The results indicated that under the load, the stress distribution shape of the web was irregular ellipse, and the stress distribution shape of lower flange and stiffener increased with the stress, transitions from oval to rectangle. The bearing capacity of the structure decreased with larger corrosion areas and increased depth in the bearings, with the corrosion of the stiffening rib having the greatest impact. When assuming a rectangular corrosion morphology for the inner web or a 1/4 oval for the outer web, the weakening effect on the bearing capacity of the structure was most pronounced.