The seismic vulnerability analysis method has been widely used to evaluate the seismic performance of bridge structures. In order to make up for the shortcomings of common analysis methods of bridge seismic vulnerability and improve the efficiency of vulnerability analysis, the Bayesian estimation method was introduced to the analysis of seismic vulnerability for bridge structures, and a bridge seismic vulnerability method based on Bayesian estimation(referred to as BEM) was proposed. Taking a typical four-span railway simply supported beam bridge in strong earthquake area as the engineering background, the vulnerability analysis of the bridge with different pier heights was carried out. The correctness of the proposed method was verified by taking the analysis results of common methods as reference. Results indicate that BEM can overcome the shortcomings of common bridge vulnerability analysis methods, improve the analysis efficiency of bridge seismic vulnerability analysis method, and greatly reduce the computational burden on the premise of ensuring accuracy. The method has good stability and a great prospect in engineering application.