We report the tensile behavior of corroded steel plates with huge corrosion pit. The behavior of corroded steel plates is not easy to predict because of its surface roughness. We therefore conducted tensile tests first to understand the behavior experimentally using the corroded steel plates taken from plate girder bridge. Before the testing, a 3D laser prove system was employed to measure the surface irregularity. In addition, finite element model was developed here to predict the behavior numerically. The model was validated by the tensile test results so that the finite element model can be reliably used for the parametric study. It is found from the parametric study that the location of huge corrosion pit affects the tensile strength, at most 15%.