Abstract: Steel structure is widely used as the main type of building structure in modern construction engineering. Many factors lead to insufficient bearing capacity of steel structure, and excessive deformation often occurs. In this paper, aiming at the continuous deformation of beams in the actual project, the main causes of deformation are analyzed, the bearing capacity of the beams is studied by using the finite element method, the reliability analysis of the beams is carried out according to the current national standards and specification, and the scheme of reinforcement and reconstruction is given. The study of this paper can provide some reference for the similar problems of steel structure reinforcement and reconstruction project.