Bridge cracks seriously affect the structural safety and durability, which don’t conform to the concepts of "green construction" and "sustainable development". In consideration of the cracks of a large beam bridge pier, an accident investigation is performed to provide the basis for the reconditioning works and to promote the standardization of the bridge construction. Taking into account these temporary connection bolts which had not been dismantled in time, their constraint effect on bearing horizontal shear deformation was calculated by ABAQUS code, then, the bearing reaction forces at pier top on three kinds of most unfavorable conditions were figured out by Midas code. After that, the pier stress were analyzed by ANSYS code. It showed that, in the case of the four temporary connection bolts are all destroyed at the same time, the maximum principal tensile stress of the three kinds of most unfavorable conditions is just 0.08 MPa, which is far from allowable value 0.73 MPa.Therefore, the pier cracks were not attributed to the fact that these temporary connection bolts had not been removed in time, others should be taken account into the investigation.